The issue is Rome wasnt broken down to pieces whenever a new ruler came in as well.
That's what has been happening at Utd for the past 8 years. Moyes' football was different from SAF's. LVG's football was different from Moyes', Mou from LVG, Ole from Mou and Rangnick from Ole. For every transition, the players in place have been quite different to what was needed. Now, I'm not going to say each of them left a mess but I would say the side Mou inherited was pretty poor, and the side Ole inherited required significant restructuring as nearly every starter was on their last legs. Similarly, the next manager will have to buy a striker, a couple of midfielders and a RB.
So, if we're going to change direction completely with every manager, we need to show patience and allow them to spend money to make the side their own. While the talent is still there in this side, we need to be acknowledge the fact that some of these highly rated players wont make it here but somewhere else as they might not be fancied by the manager. We need to acknowledge that the manager will get things wrong, there'll be high profile flops and everything that goes on at every other club as well