Yes. Go back to carts like Switch.

This basically is what i was getting at. Something like this where the old physical game can be verified once and open to download at any time. This also solves the huge mass storage issue. This authentication would have to be a one time deal though however it was done. Having to do this everytime you want to play an old physical game would suck for those who buy a next gen optical discless console. I just have a hard time seeing this happening without some kind of cost since you can take all those old physical games and sell them with your last gen console afterwards. Unless there is some way for PS/XB to block that physical copy forever once you've transfered it over to digital.

My concern wasn't with the optional optical disc drive and scenario's you presented really. More the issue that would arise if PS/XB didn't allow you to somehow transfer the physical copy to digital once and for all. That would make an optional optical disc drive a problem for people going from physical last gen to digital next gen. You would have to buy the optical drive anyway or forget about your old physical games entirely/re-purchase them.

Blu ray drive + digital only SKU with one stock HDD and a second bay for a second HDD, both upgradable.

Fuck cartridge based games.

Stacked NAND is only getting better. In a few years I wouldn't be surprised to see 128GB configurations become more economical.

As for streaming... A 6x Blu-Ray drive is only going to have 27MB/s transfer rate speeds. Which is fine for data that is large and sequential.
However a Blu-Ray drive also has high latency in the realm of 50-150ms depending on drive speed and what part of the disc the lazer is reading on.

A NAND-based device can start anywhere from 100MB/s and have latencies of a good (I'm being conservative ) 5-10ms.

So whilst Blu-ray can stream data. It simply sucks at it. It's always been that way.

HDD's are slower than a good cart, especially in random reads, but you are right about the other advantages HDD's bring.

It would be nice if one day, Nintendo allowed for it's carts to be writable so games can be updated and have DLC added.

Essentially in an all digital scenerio I think only collectors editions would have a case with the collectors edition stuff in it. I'd be fine with that.

Ofcourse greater storage space in NAND will become cheaper over time, but developers will often opt for smaller carts to save money. It always happens.

Even with HDD's you get into the greater storage for less money argument.

Anywho, we've really dragged this conversation on too long. Carts are expensive, especially for a signfiicant amount of space. They seem to work okay for consoles not pushing cutting edge visuals though like portable devices.

First huge glaring problem is with your timeline, SSD's are not going down in price and in fact are expected to rise by as much as 20% this year and is the reason you still see most laptops etc coming standard with 128gb or 256GB SSD. 1TB SSD's are sadly unlikely to be affordable in the near future for consoles. Personally I would love to see the eradication of spinning media, USB or SD Card support for physical purchases combined with digital content on a large SSD. Just unlikely to happen till well after your suggested dates (at least not at a reasonable price)

SSD's have come down in prices massively. And capacities have exploded in recent years, thanks to stacked TLC NAND and cheaper controllers.

But an SSD is not representative of the cost structures of a game cart.

With some games, you could probably get away with a smaller cart anyway. During the early parts of this generation... A significant portion of the disc space was used purely for high-quality, 7.1 lossless audio. - Which for the majority of people is entirely unnecessary, even more unnecessary with the Switch considering it's speaker capabilities in handheld mode.

During the Playstation 3 generation, developers would sometimes duplicate data across the disc multiple times so as to reduce aggressive seeking during streaming of textures and meshes, carts don't have that issue.

Carts are certainly more expensive, that's been well established for decades. But they can still be a consideration at various price points thanks to scales of economies bringing prices down and capacities up the last few years.

Besides... Publishers are posting ever-increasing-profits. They can afford it.

World isn't ready for digital-only, you'd be cutting off half your market who don't have internet fast enough or data-caps large enough to download games, especially when next-gen the games will be even larger then the usual 40/50gb.

We'll be going to the cloud when we ditch physical media on consoles anyway, not digital downloads.

Unless I am mistaken, the current consoles from sony and MS don't do traditional data streaming like the disc based consoles of old. Previously (PS1,PS2,PS3/XB,360) incorporated data streaming from the disc to system memory during play and the last gen consoles took that a little further with combined streaming from both the disc and whatever part of the game was installed on the HDD. But today we have full game installs where the streaming is only done to get the game data copied over to your internal HDD while you are playing the game. 

Now why that is all important is because it negates whatever benefits there are to be gained as far as carts are concerned unless of course the size and form factor is of paramount importance. To try and explain:

The platform holder currently expects all games to install to the internal storage. Thats because they are sure they get all round better gaming performance and faster data streaming from that internal drive than a disc. And even faster than a cart. So as far as functionality goes, all the disc (which in this case serves as no more than a container) does is allow you move its data to your internal drive. This can already be done relatively quickly and is a one time affair. 

Its important you remember that; now taking all that into account, they already have a medium that can offer great transfer speeds (internal storage), so why not opt for the cheapest container (discs) possible? Cause to use carts, whose only benefit is the improved transfer speeds is somewhat redundant, especially when you consider all the other technologies popping up in with regards to data storage.

So ideally, they should stick with discs as that will always (or at least for the forseeable future) offer the cheapest solution as a container for large amounts of data. And instead build in support for things like SATA 3 or better yet, m.2 NVMe iterfaces for the internal drives as those will offer significantly better transfer speeds than a cart could realistically ever manage. 

TL;DR, makes no sense having both carts and support for SATA3 SSDs (300-550MB/s) or even m.2 NVMe SSDs (1800-2500MB/s) as the bandwidths offers by the carts wouldn't ever be used and would instead just serve as a cost limiter. 

The price pike the industry is expecting to see now is just a temporal thing and is due to the ridiculously high demand for SSDs (of the m.2 form factor to be exact. Everyone making a laptop or hybrid device today is trying to put one into their device. It will normalize once the facilities are in place to match that new demand and when it does the prices will crash even more. 

And make no mistake, compared to what the cost of SSDs were just 2yrs ago, prices have really come down. And its all just simple economy of scale, with everyone switching to SSDs the cost of SSDs will drop. Right now you can get a 512GB m.2 SSD for as little as $150 on amazon. Thats retail pricing today. A similar drive would no doubt cost around $75 in 2020. And would cost significantly less for OEMs to aquire. Now even though the drive in question is still a sata based drive, that would most likely be the kinda drives we get as standard in the nextgen consoles because the m.2 interface would work with both sata and NVMe drives. That way they allw users swap out their drive to a faster one if they want. It would also take up less space than having a HDD bay in the console.

Nothing about what I have said or this thread is suggesting DIGITAL ONLY.