To the remastered topic: I'm not saying that it hasn't been done, PS3 to PS4 remasters era was a pretty shitty thing because of the lack of backwards compatibility, but the situation right now it's completely different, since you have backwards compatibility and a boost mode that might perfectly render any first party game remaster pointless. Is that proof that they won't try to do remasters? No, but again, the scenario is just not the same.
Backwards compatibility: The thing is, Sony is equally allowing third party developers to offer free upgrades from current PS4 titles to PS5 with any and all improvements they see fit to have in their games. So, you will effectively have a PS5 version of that game too.
Smart delivery is a nice thing, don't get me wrong, it automatizes all that. But my point still stands that I think it makes most sense for Xbox, because of the cross-gen nature of their first party games, at least for the first couple of years.