The big problem with such a move is that there are so many people who buy a console for Fifa, CoD and not much more. Some of these people will definitely switch to PS5 if they need to pay 10 bucks a month to play CoD or Fifa.
It might be a better deal for people like me and many others but for those who only play the same damn CoD, Fifa, GTA? Nahhh...
And if I want to play these games with my friends who will move to PS because of that? Well, then I also need a PS just for that.