I think people need to realize that MS is not concerned with selling systems really. They are interested in active users and or subs.
So they want 2 categories of games, one being a game that adds value to gamepass. That's a game that isn't free to play but is included in GP. And two, a game that has its own way of capturing monthly or seasonal revenue.
I think any game that is likely to draw customers or keep customers in Gamepass will be exclusive. They need new games at a decent cadence to keep people paying.
Any game that is free(or makes more $ from GaaS) and doesn't add value to GP will be available as many places as they can get it. They want as many season passes as possible.
Thirdly games that don't really add either will be case by case.