This thread title is really, really hard to get my head around, already poked to see about having it reworded slightly.
As for the PS5 and neXtBox (coining this now) they wont be fully backwards compatible. That is to say... software wise they might be very close to backwards compatible, but do you really imagine that neXtBox will have the port to connect the Kinect2.0 to in order to play Ryze or Fighter Within? How about the PS4, do you think it will be completely compatible with PS4's PSVR? The move from the PS3 which is used with the PSVR, or even things like the controller from the PS4 when you need to use the motion control and the little mouse touchpad thing on it? I think games which rely on specific hardware... Skylanders and Starlink both come to mind again where they have a thing which needs to connect to the PS4 in order to play. I can't see both systems being able to give 100% backwards compatibility.
Mark Cerny had confirmed PSVR will be compatible with PS5. PSVR2 will probably take a year or 2 to launch.
About OP, I don't care about BC, I have a PS4 and will keep it when I buy PS5. But considering this gen, once I buy PS5 I'll hardly turn on my PS4. But enhanced version of my favorites I may play again.
Still from the interviews it seem like they will be BC day one. Now about they having everything I was thinking Apps, UI, etc. And that isn't a problem for me as well. But considering the backlash the start of this gen, I expect that at least all apps available now will be on the release of nextgen.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"
Azzanation: "PS5 wouldn't sold out at launch without scalpers."