Update, January 23, 2018: We asked Microsoft if this meant that upcoming Microsoft Studios would be permanently included as part of Xbox Game Pass, to which they replied that all games would continue to cycle in and out of the pool of available titles. While that didn't answer my question directly, it sounds as though Sea of Thieves, State of Decay 2, etc, might only be available in Game Pass for a limited time, before they become available to purchase permanently at a discount. We've asked for further clarification, but Microsoft said that was all they had to share at this time.

https://www.windowscentral.com/all-m...moving-forward