Yup this is clearly another case of Sony squeezing their fans for every penny they can. There is literally no justification for this really at all except Sony just taking all their loyal fan bases hard earned money.
Sony does this with PS Now and makes you buy games again for most games. And now this. You can't possibly justify saying that a PS4 controller would not work on PS5 games. You just wouldn't have the trigger feedback whoopee doo or less vibration but this is a joke. This can easily be turned off in an option tab for games or something simple.
I know their is already a thread on PS5 and DS4, but it's specific to just the PS5. This thread is a debate for both XSX and PS5 based on new updated information as of today.