Totally agree. There's no chance he gets an extension at United and arguably the only reason INEOS don't move him on is if they feel they need more time to get the executive team ready. It's a sensible outcome for both sides.
I don't hold with the idea of their being no "outstanding" candidates being sufficient to stick with him. It seems the manager becomes more of a head coach under the new system and there are no more or less decent coaches around than their normally is. Outside of a Pep or Klopp, or perhaps Ancelotti or Zidane, it's mainly coaches building a reputation who may, or may not, prove to be good enough. A manager's stock is always rising or falling. What's going to change in a year other than some have a good season next year and some don't? A potential candidate might have another good season, but then still not be good enough if he get's teh job and has to step up.