Microsoft is considering increasing the price of Game Pass Ultimate again. It's also had internal debates on whether to put new Call of Duty releases on Game Pass.
I always think about total of games purchased / 12 for a per month. If I buy 1 AAA game every 3 months, that's 4 $60 games, about $20 a month. I'd say Game Pass is going above that. Argument could be made that there are games you wouldn't otherwise buy.... but eh?
I bought for my kids on the 3 year conversion deal. It's great for them. They can try all sorts of different games and have played stuff they never would have otherwise. Since I generally refuse to buy on release day or preorder, them being able to play newly released games with their friends has been pretty cool too.
I ain't paying $15/month/per kid tho. That's crazy talk.