This piece covers a few bases.
https://www.football365.com/news/ole-gunnar-solskjaer-solution-man-utd-opinion
Perhaps the issue isn't solely recruitment, injuries, the Manager, the quality of players, but actually a little bit of all of them?
Without reading the article, but yes absolutely. Ultimately all of those come back to the CEO and beyond him the board and owners. Manchester United is (at least from the outside) a completely dysfunctional organisation.
Focussing a little tighter on the football. We have had such a balls up around players because after Moyes we completely abandoned United values to appease a certain segment of fans. LVG started by implement his rigorous, boring, disciplined system. Mourinho then not only threw out the remnants of United but he threw out the remnants of LVG as well.
We now have a manager who is setting us back on the right track. Hopefully he can stick around long enough to make sure that the next manager has a base of players that fit with the club's philosophy and more importantly the manager does as well.