It's a sub. Sub has to cost low to be appealing.
This concern is weird honestly. Game expectations shouldn't change, and these games will still be sold full price for pass AND and none pass subscribers. Netflix didn't change the movie industry even when it boomed, if anything it helped by having a place for mid projects/shows. Netflix also puts a lot into their own originals, to meet the people's expectations, and let them keep on subbing for amazing content.
Microsoft will keep doing just that, keep making great content to make gamepass be worth a sub. Once the content starts changing because of concern of cost, it will only hurt the appeal of gamepass overall which is something Microsoft doesn't want to happen.