According to what was reported by VGC, Gran Turismo 7 it would become a title cross-gen only recently, unlike Horizon Forbidden West and God of War: Ragnarok, which have always been conceived as titles also intended for PS4. This would explain why Sony unveiled it as a PS5 exclusive again in December last year. If we want, it is also an indication that we will not see it anytime soon, given that the times to make a port of such a complex title are certainly not trivial.
If desired, this is excellent news, because it shows how almost any game can be converted for other systems, even old ones, obviously at the price of some graphic sacrifice. After all, we have seen several miraculous ports for the Nintendo Switch, so it is not clear why it should be impossible to scale a game from PS5 a PS4.
However, PS4 owners will also be able to race aboard the racing cars of Gran Turismo 7, albeit on a date yet to be decided.