I see this as a likely route too. Although maybe one notch less than you perhaps - he MIGHT level out at the bottom end of the PL. The main concern there is that even lower down the league now all the clubs are trying to get progressive coaches in and rebranding the football they have traditionally played. Even they may not see any use for a centre midfielder who has a penchant for passing to opponents and ball-boys.
Whatever happens, he’ll retire as one of the luckiest footballers I’ve seen in my time watching football. He’ll probably have had a fair few hundred PL games, many as a starter, 6 years at Manchester United, international tournament experiences, big CL nights in places like the Nou Camp, EL finals when in reality, if he had been released from our academy instead of being promoted and went on to join Forest Green Rovers - nobody would have batted an eyelid at the time and I imagine he would have struggled to make it from Forest Green to the PL.