PS4Pro started off "slow" due to a clarity on what's new in the console for its price. This is something Sony needs to learn from MS and Apple (other mobile comopanies). PS5 will be seen as providing a lot of new value over PS4/slim/pro due to mostly marketing, new physical design, and OS improvements. While to Sony this will be seen as largely similar to a PS4Pro shift. 

I'm willing to bet that MS will see a bigger response to Scorpio from existing Xbox One owners than Sony did for PS4Pro from PS4 owners. This is going to be almost exclusively due to marketing and perception of value. Scorpio has always been touted as a big jump in power even though it is not being presented as a new console, just an upgrade. Whereas with PS4 the marketing was messy and not clear to value of an upgrade. PS4Pro will do better as price/bundles provide that value. This really is similar to when they just announce a new SKU with a larger HDD. They don't blow up the market but they do well over time.

I don't agree with the idea that games are held back or are harder to develop in this scenario. For almost 2 years after PS4/XboxOne launched, the same games were launched on both gens. That was possible due to middleware allowing relatively simple build process between existing hardware and new pc-architecture based consoles. When folks talk about 3rd party support for lower powered systems such as Switch or what will be PS4/Pro once PS5 is launched, they ignore how middleware / modern dev tools actually work. They ignore that consoles have moved to be PCs and like PC gaming, the dev tools allow relatively simple scaling for a very significant amount of the dev work. (there are plenty of articles on this if you google how it works) Tools like Unreal Engine allow devs to literally change one setting / one button and build the game for a different platform based on preset information. Once that is done, they then refine settings to normalize the build and remove any porting defects. That work is of course variable, but no where near the same amount of effort for say porting to Wii from PS360, etc. Creating a game that can utilize PS5 (or Pro) when designed to do so from the start will not have any impact to it still working on PS4. You saw initial issues with this at PS4Pro launch due to games needing to be retooled for the PS4Pro. This was a one-time cost as these tools were enhanced for PS4Pro. Games being designed / built now (like Red Dead Redemption 2) will not have these issues.

Also, I (while not the norm) never subsidize my phone and that (subsidizing) is only a norm for US (afaik) but not the norm in other areas of the world.

Yeah, I'm clueless in regards to making a PC.

I suppose the tendency will go towards hybrid consoles. People who do a lot of business trips and are mostly away at home will consider this one like me.

Very near future - traditional consoles and PCs

Future - Streaming and standalone VR...especially streaming - once internet is good enough when it comes to latency, traditional publishers will jump this train and never look back since it gives them complete control over content and pay models, plus there's no second hand market and piracy.

Distant future - Volumetric display consoles (which will combine video and board games) and (for the lack of better term) Brain Injected VR.

Look at the 2 most graphically acomplished games atm, Uncharted 4 and HZD. Would they be as good looking if it had to support a ps3 version as well? Could HZD still look a lot better if it was a PS4 Pro exclusive? All it does on pro is raise the render resolution. That's what you get with scaleable engines. The base version still determines the limits of the gameplay elements.

If PS5 has over twice the memory, twice the cpu cores etc, gameplay will be held back by supporting the base ps4. AI, physics, map size etc will all be limited by having to run the same on the old models. Which makes it possible to run the game at 4K60 on ps5 while 1080p30 on ps4, but it's still a ps4 game. Yet perhaps that is what people want :)

If Google planned well PC takeover by Android, it's to late for MS to stop it, and we'll have a unified PC+mobile platform, while old Wintel PC games will be dealt with emulators. At that point we could also have Android on some consoles, but heavily customised, each one with dedicated optimised drivers for a single HW platform and a small number of different configurations and with mandatory proprietary marketplaces.

What you are describing with HZD is that a game was built on PS4 and is being scaled up to PS4Pro. That is not what I'm describing and that is not how it works in the real world.

Games would be built on the new / latest hardware and then scaled down to allow acceptable performance on the lower-end hardware. This was most evident with Call of Duty games (yes not system pushing games) being built on PS360 and then retooled to work on a far lower-powered Wii. However, this scenario also required a full port as the Wii was not on similar PC-like architecture as PS360 and also a poor representation of what PS5 to PS4 will be.

The difference is that consoles, again, have changed to be PCs. They are no longer simple dedicated game consoles that require special engines for game development. Instead they use the same tooling as PCs and allow a wide variance of build functionality. This is one of the reasons all three manufacturers have gone this route. It saves them time and money to support many different consoles plus PC. This is exactly whey MS is building Scorpio, something that will be significantly more powerful than the Xbox One/PS4. 

In the end, I think you will not see a PS4 game running on PS5, but a PS5 game running on a PS4. I think you'll see this by holiday 2018 with Scorpio games running on Xbox One/PS4 and this will not be a bad thing for consumers. It will instead be a good thing. Constantly improving hardware (every couple) years to satisfy any gamer's needs, constantly improving games, constantly improving features and great flexibility through the availability of a "current gen" console at a low price point.

Eventually everything will go digital and become insanely expensive.

We will see one more console generation after the XB1/PS4. The PS5/XB2 will launch in 2020 and that generation will last around six years. After that games will be all digital, and will be extremely incomplete on release. They will be sold piece by piece in such a way that you have to pay $100 for the same amount of content that you get for $60 today. Or you will have to pay for a streaming service just to play said game, and it will cost you $20-$30 a month. Also your save files will be held at ransom in the same way that Adobe holds all your photoshop files at ransom on the cloud.

[Offtopic]PC games aren't cheaper than console games. Dark Souls 3 is $24 used on consoles, but the last steam sale only had it at $30. You can get brand new console games for $45 with a best buy club membership. The same games on steam costs $60 on release day.[/Offtopic]

It seems Google is getting ready to make Daydream big. They just announced new standalone headsets, inside out worldsense positional tracking for Daydream 2.0 (Euphrates), a new tool (Seurat) to render desktop level graphics on mobile vr (already in developers hands), AR Api and daydream support for Google Chrome, Chromecast for VR headsets, sharing screenshots, inviting friends. That's starting to sounds an awful lot like a new contender.

And while tech might be slowing down in the normal console experience, it's going blazingly fast in VR territory. An eye tracking add-on is coming out soon for HTC Vive, which can double performence combined with Nvidea's hardware level foveated rendering or let you shoot lasers out of your eyes! There's already a 4K headset for $400 on the market and they're working on an 8K headset. NVidea is working hard to improve foveated rendering to the point you can't spot the difference anymore which could make the race to high-fidelity vr take less than a decade to achieve. The higher res the headset, the bigger the gains from foveated rendering.

Well, to be fair, Seurat is more of a nice trick that I doubt is very useful for anything outside of very on-rail experiences....but really nice looking nevertheless, and people that don't really do gaming will be blown away with those experiences on mobile VRs.