Wow you are going really far into the future with your question positioning, but you mix it too much with limited modern functions.

Mobile is going to be the future for now or, at least, more flexible systems, however I do not think it will be phones. Phone functions may be important but that industry is not where the change is happening. I think the industry most likely to be the base for future devices will come from a large company like google, amazon, or Facebook for various reasons or, even more likely, a company currently in the video game hardware market, preferably creative Nintendo. Whatever comes from this will not be considered a phone but will have phone functions and until it comes out, we will continue to have incrementally developing phones like we have today.  

It may take another two or three generations of changes, picking up VR and upgrading systems along the way, but we will likely have a different device that is at its core a computer with entertainment/game/navigation interface with phone/communications functions with ability to interface with smart home functions and incorporate holograms/AR/VR into the UI. It will also have some interfacing with car systems, but the car market moves much slower. It will likely be of a form and possess controlling methods we do not see as mainstream today. I see all major companies today having a role in its development either historically or directly at that time.

There are too many random tech advances and trends developing right now to go into more specifics. Now, if you want to talk about all the possible steps to get us to that point, then this thread could go on for months if everyone plays along. 

*This is of course with the caveat that the world doesn't destroy itself or we all end up under some oppressive power.

So you basically foresee the comeback of the pda. It should happen when mobile data networks become more open and more mobile devices can connect to the internet from anywhere. But I think it's more likely all your data is going to be in the cloud instead of on the device, most of it already is anyway.

About that world destroying itself, it seems the AI revolution is starting to happen. I was following GTC 2017 for VR news, yet what stood out to me was all the advances in AI: https://blogs.nvidia.com/blog/tag/gtc-2017/?doing_wp_cron=1494621353.5327520370483398437500
AI for self driving cars, medical robots, accelerating health care, interpreting sign language, reading and predicting your emotions, story telling, raytracing, product creation and many more. NVidia is really promoting the use of AI in business solutions.

Interesting times ahead.

I think the headsets are an inevitability, more AR than VR (to avoid walking into traffic, etc.).

By that time the headset can do the walking for you while you play a game. With the reverse of the mind controlled wheelchair, the headset can use inside out tracking combine with gps to steer you through traffic ;) Or it can make a virtual representation of the real world for you to walk through!

Okay, you're looking waaaaaay down the road, and I don't disagree lol.

All we have to do is look at the iPhone as a clear example of mobile upgrade cycle as well as the future of gaming.

Each year Apple launches a "new iPhone" with these exact upgrades:
1. More powerful CPU/GPU
2. Better screens/camera/basic functionality (in some variation)
3. Latest version of OS

Every 2/3 years Apple changes the physical design. This is the only time the actual number of the phone changes.
i.e. iPhone 4, 5, 6, and 7 all look different. Yet the 4s, 5s, etc did not or had very minor changes.

The normal "slim" models or now "pro/scorpio" models are akin the the 's' versions of an iPhone. These are what you are claiming as "upgraded hardware". Yet, the physical design changed versions (4 to 5 to 6, etc) are actually the same thing, just a different box. They have the same actual changes with the rare exception that they add a real hardware feature change such as the addition of fingerprint or connection change.

This is why, even the PS5 is going to be "upgraded hardware" but not a new console gen clean break as you are defining above. It will be a new look, upgraded OS with new features, upgraded hardware for power/etc, but it will be based on the same PC-like architecture that MSony both switched to this gen (and they did so for this very specific reason).

It is a costly enterprise to create an entirely new console based on entirely new architecture. The rising costs of building games on hardware with zero userbase is extremely risky. However, if you build a platform that can be continually upgraded every few years, then you gain the ability to always have a large userbase to sell to.

PS5 will exist. New look. Updated OS. New features. Clear power difference to allow new gameplay/graphics/etc.
PS5 will support the same existing and new middleware. This allows the same game to be built to take advantage of PS5 while still working flawlessly on PS4/Pro.
- This reduces risk from lack of userbase.
- Still allows devs to continually improve tech without rewriting entire engines, etc.
- Reduces R&D costs for console manufacturers as well; including their own risk for new generations.

This is also a major reason Nintendo moved to a PC (mobile) like architecture. They can benefit from the same like-ness of middleware and dev tooling as MSony will have. Improved scalability means they continue to remove barriers for 3rd parties as well as reduce their own R&D for new consoles.

At this point onwards, "console generations" are simply not anything but marketing. You can easily skip a version to remain on the typical 5/6yr cycle and not miss a game OR you can buy the 4, 4s, 4Pro, 5, 5s, etc every 2 years (or so) and remain with the cutting edge.

What will remain to be seen is when the PS5 launches, will the PS4/s/Pro get the OS upgrade too or will that be a forcing function to push people to upgrade? I'm betting that they will want to keep up the idea that this is a new generation, even if the core of the OS is the same. This isn't too far off from phones either. Apple / Google allow support for the last few versions of their phones only. Other manufactures (entirely Android) do it for only the top-line phones and only a couple versions.

In 100 years, it's going to be all VR. We'll be using our natural bodies instead of controllers and jump into fictional realities. So basically, the future is going to rely less and less on home console gaming to the point where it dies off completely.

by the time that happends, the rich will have enslaved the rest of society "to do the walking for you" (in a factory).

Whos first in line to get a chip in their head? where do I sign up?

Seriously though, screw ever trying to walk around playing a AR game with a headset on, outsides in trackfic.

I hope VR takes off, and AR kinda dies off.

I dont wanna play small silly games, where characters interact with your surroundings ect.

Id rather just go fully inside the game then, as VR allows.

So do you expect ps5 to start off as slow as ps4 pro? Games will be seriously held back in they still need to run flawlessly on the base ps4. Which will make ps5 just look like another resolution upgrade. Now the same thing in full 4K. Plus it adds more work to development, slowing releases down with multiple builds that all need to be tested. Rewriting engines every 6 years keeps innovation alive and gets rid of legacy code. Or you end up with more stuff like Skyrim on the ps3, pushing a creaky old engine to the limit to save costs.

Yet perhaps with the right maketing it will work. I works for Apple. Yet the peer pressure to get the latest phone is very different from consoles. Plus phones are heavily subsidized since you already pay a ton for the subscription. It didn't work very well for ps4 pro, why would it work for ps5 if it's just another incremental upgrade?

I rather have console makers work for their userbase instead of doing the minimum to keep them from leaving :)

It wouldn't really be a pda or a smartphone or a gaming device or remote control or any other singularly defined thing that we know today.  The easiest way to describe in today's terms would be an HOD interface, but it does not necessarily have to be a head mounted device.  It could be a wristband, shoulder strap, lapel pin, or some other form that hasn't been thought of yet.  The person who does come up with it will be that generation's Bill Gates or Steve Jobs.  It wouldn't hold any data necessarily but would interface with all data remotely using the cloud or cloud-like technology.  I do think security methods will be panned out around the same time, not eliminated, but more controlled and reasonable. 

As far as AI, it is a player in all of these developments, but I highly doubt it will be a driving force or anything other than a slave to necessity for some of these transitions.  For instance, Amazon Echo and Google Home in their limited functionality is something that we should have had on the market 6 years or longer ago, however even in their current state are not developed enough to become a cultural phenomenon.  There is so much potential but so little interest in developing the tech beyond the initial device.  Sure, we will have better iterations of the existing tech that will generate new companies with personal home robotics, but that is such a hazy prospect with current trends.  It will happen, but not fast, similar to the car industry.  This tells me that the pull for better AI is limited to market necessity, not demand.  Both Amazon and Google probably see the potential for the tech on society, but seem to be somewhat satisfied with its gradual progression.  Other tech though like VR and Hologram technology as well as the game market that is driving a lot of it is much more driven and competitive.  That is why it is more likely that movement is going to happen there first and then incorporate through partnerships these other elements along the way.  Whichever industry creates this device will determine how we look at it.  If it first is developed in the game hardware succession, then we will traditionally view it as a game system; If it is derived from the phone industry, then we would think of it as a phone; etc; etc.