I see lots of crying and complaining for no reason here.
That just confirms you haven't properly read the thread. Understandable given the number of posts and pages but try to at least understand the different points of view before commenting rubbish like that.
GT7 will be a true next gen game and the PS4 version will be a very downgraded thing in terms of graphics, thats about it.
Just like a high end PC (PS5) and a mid-end PC (PS4) they can run the game exactly the same but the high end one can run it on much higher graphics settings.
No problem at all except that PS4 graphics will be far from optimal since the game is designed to be played on PS5... but it should have enough power to handle everything with a low enough settings
And this is why you've completely missed the biggest points about cross gen games, the greaphics are not the problem. The problem is, if the only difference between the games in graphical, and not functional, then the PS5 version of GT7 is not what it should/could be. It should have improved physics, features, AI and the list goes on and on, but these are things that become problematic when it comes to a cross-gen title as the core game functionality tends to remain the same.
PS3 could handle dynamic TOD and weather so PS4 can too.
GT Sport most certainly couldn't. While some games can, everything is a trade-off, calculations per second to improve the physics, AI, dynamic time and weather or pre-baked, resolution, number of cars on track at once, making one thing better/more complex requires a trade off on how good other things could be. By making GT7 a cross-gen game, the PS4 becomes the baromoter for many of these things rather than the PS5.
With low enough graphics PS4 could handle everything that the PS5 does. It's all about optimization. Playing it on PS4 will be far form ideal and optimal if you want the best visual experience though, thats for sure. But other than that, it should be ok.
No it can't, the PS5 can process many times more calculations per second than the PS4, that means the AI, physics etc. can all be better on PS5 than on PS4. In additon, the level design can be better on PS5 over PS4, that means larget track environments with more trackside features etc. THe capabilities of the PS4 are not infinite everything except graphics. For exmaple (and if you'd read this thread you'd have seen this comparison already) the PS1 could not run GT3 game engine with worse graphics, likewise the PS2 could not run the GT5 game engine with worse graphics and the PS3 could not run GT Sport with worse grphpics, because all of these games made progress in ways you can't see as well. There is so much more to a game and game design than polygons and resolution, that's just the tip of the iceberg.
Like I said, it will feel like playing a top game on PC with much lower than maximum graphics settings. Obviously a lot better on PS5 but playing on PS4 will better than nothing.
And PC games all have different minimum specs, and those are the baromoter for the games features, not the spec required for ultra settings. Higher specs just provide better graphics not more features. In other words if the PS4 version of the game doesn't have dynamic weather, time of day etc. the PS5 version in all probability won't either regardless of if the PS5 could support it should the game have been designed with it or not.
The only way to make a PS5 game playable on a PS4 is to design it with the PS4 as the minimum requirements, which is what is needed to develop a cross-gen game. If you design a game that takes advantage of the PS5 it will not run on the PS4 (certianly not in a stable and/or playable state) no matter how much you downgrade the graphics to accomodate.
In fact, a game that makes full use of the PS5 in every way except graphics would in all probability simply crash a PS4 while it started up.