Don't think it's as simple as that. Chelsea flogged Lukaku and De Bruyne because they were deemed not good enough for them. Man City proved them wrong and Lukaku is firmly on his way too. SAF clearly rated Cleverley and I take him a lot more serious as a top class manager than Moyes and LvG.I think it would be hard to argue against this. The reason United got rid of him is because he clearly isn't top 4 quality.
Manager, tactics, position, playing style and confidence play a massive part in any player reaching his potential.