Why are you comparing one season to another season? Every season is it's own thing. There can be 40 teams in the top division and United having 100 points doesn't mean anything if they don't win the league or finish 10th. It's about the final table results, who the feck cares about total points compared to previous seasons.
So if you're now saying that United statistically had one of the best defensives in Europe based on goals conceded, then doesn't the manager have something to do with that? And then you compare that defense to the current defense through 3 PL matches....same exact players, but they are severely underperforming due to a major factors and some reasons can include the manager, but the players are making way too many individual mistakes and are getting punished for it.
See that's where you aren't understanding the point of having football men in charge of the football side of the club. If the manager sets out targets that are too overpriced, then you communicate that to him and you work with the scouts, your network, managers, coaches, recruitment head on identifying players who can provide the input needed for the right output (results) for the first team. You don't think that Woodward is telling Ole, hey this is our budget, this is what they are telling us and these are the fees...we need to move on and here's what we're trying to get and here's why. But from many sources, United aren't conducting business with other clubs directly, too many intermediaries for too many peoples likings. And if you do business with middlemen, you know that shit isn't always smooth sailing and that you're at the mercy of someone else trying to conduct business you don't exactly control...and that's frustrating. Sometimes it has to be done that way, but usually you incur additional expenses and stress when dealing with middlemen...and that just shows you're kind of inept or don't have the resources to conduct all business transactions if you're using middlemen. Which is okay to admit, but when you're the size of United and claim to have all these financial resources and means, you shouldn't be doing that.
It's not even showing more confidence in the players they have, it's knowing the fecking gap between United and Liverpool is significant and if you have a target of challenging for the league this season, then you better get them reinforcements of proper quality and then the proper time to get the players, current and new, up to speed not considering injuries, suspensions, etc.
Hiring a better manager or more innovative manager than Ole isn't difficult....what is difficult is having that footballing IQ at the top of the club and having it go through the club. Good managers need, always, good players to be good teams. You can't make a cake with shit. You could make it a little better, but you can't make cake with shit. And that doesn't mean signing the world's most expensive players...it means having a system that brings in quality consistently at good value and you're understanding that the players who come in at different times can and hopefully will overlap in terms of optimal or near optimal performances so you have a mesh of young, older, old/experienced heads and losing one or two players (or managers) doesn't mean you're starting from zero, but able to carry on for the most part if not improve.
Bruno didn't 'save' Ole's job...he made the team better. As did Martial, as did Greenwood, as did getting Pogba back, as did Matic, Fred, and McTominay doing their part. As did the defenders, as did DDG. You win as a team and you lose as a team, but the manager will always be underappreciated and overappreciated.
Having competent players isn't saving a specific job, it's just a competent and realistic thing the club should be doing. Neglecting the right wing for years after Valencia went to RB wasn't LVG's fault, nor Mourinho's...don't you think if you're in charge of the football club like Woodward and whoever else, you look at your product and say, hey....we're kind of lagging on that position or from what I've seen across the leagues, seems to be lacking...hmmm...maybe I should bring that up to the relevant people at the club and see what they think, but because I'm CEO I'll make the decision on behalf of the club...since that's my job after all.