In re games being designed to stretch out play time instead of fun and interesting time, I think players would pick up on this pretty quickly and simply stop playing those games.
This is not at all what will happen. Developers will gravitate making a certain kind of game to be designed to consume the player’s time with just enough engagement to keep them invested. It would cause other genres or styles of games to be pushed out, since they would not be able to be monetized in that way. Payment models like this are bad for a healthy ecosystem of game development. Only certain kinds of games can succeed. It would encourage development of games that are not respectful of players’ time as the developers attempt to optimize their revenue.