Phil convinced them that if they could not compete that was their lack of studios (which he closed in part).What I don't understand is why Phil Spencer & co aren't fired the fuck out of there already. It's been a decade straight of continual failure. These aren't the first games that have disappointed. If they can't find anyone internally who's willing to step up (and with an excess of 200k employees I find that highly unlikely) then they need to find someone external who can come in and clean house. That's if they're really committed to the gaming thing and not just doing sunk cost fallacy because there revenue numbers will nosedive without it.
So they gave him tons of money to resolve the situation and do acquisitions.
He could show them how gamepass was growing for a while, so that might have looked like success. Hey look at this growth, it probably go to the moon!
He has a cult following and the shill army probably prevented a few internet backlashes from happening (or they made enough noise to kind of hide the real mood around Xbox).
So there might have been enough to fool the casual bean counter.