I don’t think Microsoft will do so, at least in the foreseeable future. One of their selling points to devs is that they’ll see their sales go up in addition to the GP revenue. There would be a lot of publishers who would pull out if they can’t sell their game and have it on GP.
They might do it for their own games, but even that could be a stretch. Starfield saw huge sales on both Xbox and PC in addition to those who are using GamePass.