The old consoles will be kept going for a while yet I think. There's lots of places where it's simply much more affordable to get an old gen console, not to forget the supply issues with the new ones if cost isn't an issue.
Yeah they usually keep supporting them years after a new generation is out.
With the global component shortage resulting in a low supply of new gen consoles, I wouldn't be surprised if the life cycle of Ps4 and Xone gets even longer than usual.
Devs/publishers want to make money, so not releasing a game on old gen if possible would be kind of stupid considering the install base the Ps4 for examples has.
Last time I saw the sales numbers there were around 116.000.000 Ps4 sold vs around 14.000.000 Ps5's.
