I might be willing to pay a monthly cost instead of buying games individually if the catalog was comprehensive. The problem I've seen with services like PS Now is that I'm not interested in many games, and there's always a bunch of good ones missing. I'd probably be happy with a service that had all games but you picked like 3 or 4 a month you were going to play and then waited til next month for more pics.
Xbox Game Pass is pretty similar to that (and also on PC), minus the whole streaming thing of course. I almost signed up for the trial but the last thing I need right now is more games.