I think you're being a tad bit hysterical re the boldened. Irrespective of what happens to Ole hereon, he's almost totally revamped the squad from the Frankenstein's monster that it was under Jose (who largely didn't bother clearing out the shit he inherited from LvG), and LvG (who turfed out perfectly good squad players in favour of the aforementioned shit). If the next person comes in, he will have a coherent squad that can be moulded to what he requires.
It is one of the youngest squads in the league and in Europe, with a front line that is a genuinely frightening prospect for any team that crosses its path. We also have a very strong, varied and flexible collection of midfielders. So much so, that you could arguably call it our strongest area. Our GK situation is also probably the best around (with the possible exception of Bayern) - you only have to look at how we were during that post-Schmeichel period or Chelsea right now, to see how much of a destabilising effect it can have on the whole team when the GK transition is bungled.
The areas which need resolution are the obvious ones of DM, CB, and RW and hopefully Ole will be able to rectify those positions next season, but if not, then you'd hope that the next man will be given that opportunity.
Also, SAF never won anything with THIS squad. Moyes had the same philosophy as what you are suggesting with that squad that SAF had, and look how that turned out. Just because the greatest manager of men and resources the game has ever seen could do something as remarkable, doesn't mean anyone else could. Also, what deadwood had been shifted under Jose? As far as I can remember, it was only Schneiderlin, Schweinsteiger and Depay. That's it. Ole probably doubled that number of outgoings in his first summer alone. And with LvG, we know what he did, and shifting of the deadwood really wasn't it. Neither did Moyes. He actually made a point of keeping every player, and gave second chances to Nani and Rooney with 5 year contracts for both. The only manager who bucked that trend was Ole, and likely it was only because he had that 7 month settling in period before his first summer transfer window.
In fact, the reality is, every manager that has come in has actually sought to give every player a new chance. It's partly why the likes of Jones and Smalling stayed as long as they did. Every manager that is, until Ole. So I'm not sure where you're getting that from, tbh.
While I agree with you that we should ultimately go with the model that several of our competitors have, we right now, do not have the system in place, despite having the means to do so. If you want us to do go down the short-term coach route, then we'd need a stellar DoF and Administrator, who would ensure that there is a sense of continuity in the project. We don't have that, and until we do, we need to back the managers and ensure that their vision is brought forward on to the pitch.
