Will be the same as usual in my opinion. Old consoles will get supported as long as there is enough reason for the devs to put games on them. Not everything comes down to power. Despite both PS5 and Series X being quite similar to PS4 and Xbox One in terms of hardware (which makes porting games easier), they use different SDK and dev tools though. As far as I know, if a game built using the SDKs for new consoles, this SDKs can not target older consoles, so it would require additional effort to port such game to older consoles. You know, some devs already started announcing PS5/Series X and Switch as platforms for their 2022 and beyond games for a reason. They just don't expect enough active audience to stay on past gen to make it worth porting the games to these platforms.
