Yeah, you're describing PC basically - 10nm should be available by 2017, so mature, cheap 10nm in late 2018 is quite possible, if not that, then 2019 - that will allow them for standard 8x jump, if they wait for 2020, even more.

Devs are already making their games on PC scale that much, so given most likely very similar architecture and OS, it's quite probable that vast majority of titles in first few years will be cross-gen - later, however, I don't think so.

No excuse at all. I imagine that any game you buy on the PS Store will be able to be downloaded to your PS5 the day you buy it.

I doubt it. Graphics have nowhere else to go (unless they drastically increase the budget of the game). So, because visuals will stay mostly the same, things lik framerate and resolution will go up. Similar to how Uncharted 1-3 went from 720p/30fps for the PS3 to 1080p/60fps for the PS4.

You literally just described the PS2/launch PS3...new games exclusive to the platform but will natively play previous gen titles.

Nothing will change. We are reaching the point where visual leaps will look smaller no matter how great they are due to the quality we have been able to achieve already. However I have said it before and I will say it again, there is more to these leaps than raw graphical power. There is also processing speed, AI, visual effects outside of resolution, physics, draw distance, and how much info in these virtual worlds can be processed at once. People need to lose this idea that resolution and framerate is what decides the leap, it isn't and it never will be. It will always be saught after but the only platform that can realistically keep up with it is PC. Consoles will continue to push boundaries in other ways and I asure you there will always be a big enough leap rendering last gen obsolete when true current gen focus is given to a game.

In short no, this will not be the case. It was a nice little theory, but far too flawed to be reality.

If you put it like that, it does make sense. If done right it does have a lot of potential.

PC games are always made with a min-recommended-max spec range. As long as PS4 and PS5 are as similar as low and high end gaming PCs I don't see co-development for PS4 and PS5 as being a problem for getting the most out of PS5.

What might be also possible with PS Now is that if you buy a PS5 game for PS4, then you could play the PS5 quality game on PS4 through PSNow. If streaming is to become more of the norm for games, then a start towards that transitio is making it possible to play the better quality game through PS Now.

I think PS5 will be VR focused and produce a slightly improved level of graphical fidelity to PS4, but at 2140p(or 4k)/120fps for compulsory VR support of all games. So the hardware will be significantly more powerful but the least dramatic of all generational leaps so far. If you choose to run games without PSVR a few graphical settings will be upgraded. It will have backwards compatibility with PS4, and there will be more cross-generational titles than usual, but eventually PS4 support will be phased out. It won't come with a PSVR headset but will be an exceptionally cheap console ($299) to encourage users to buy the headset in addition. 2020 release.

The inability to make a considerable in jump is graphical prowess/power in general is what makes me think that Sony and Microsoft will look to Nintendo to get inspiration from.By that I mean that they will rely upon a "gimmick" to sell the next generation.
And my guess, at least for Sony, is that VR is going to be that gimmick.That is also a reason that Sony is wanting to market it so much.There are two reasons in my opinion:The first one, is to test the technology and see how feasible it is to sell at a mass market(trying to find the sweet spot for prices and so on).But the most important(second reason)reason is to get people accustomed and popularize the idea of VR being used in a gaming device.And as many users already said across several forums, VR is extremely hard to promote, and the best way to understand the potential of it, is by using it and seeing for yourself.
It will be really hard to try to convince people to upgrade the console when there is next to no difference betwenn them.So making the experience unique to the PS5(in this case) is crucial for its selling point.

One of the big issues is going to be that games that come out on the PS4 are going to need to look and perform up to the standard this generation has set. Let me explain;

Lets say that The Witcher 5 comes out for the PS5, and it's world is twice the size of the map in The Witcher 3, has more NCPS, more foliage, and is just in general much larger. There is no way that game would work on the PS4 while maintaining a level of fidelity and polish that gamers have come to expect from a PS4.

well, it almost happened on ps3 to ps4. 2 years and you can play 80% of ps4 library on ps3...

it could happen.. but they would? trying to sell new hardware would demand exclusive titles..