Of course it's a positive, but that removes the need for a manager entirely. A monkey would be doing better year on year with hundreds of millions of pounds being added to the playing squad. What's the point of the manager if you don't care about whether he maximises the output of his players?
Other teams invest hundreds of millions as well, which makes it slightly more difficult to do better year on year. But we're (in my opinion) doing better than last year, while some other teams (the almighty Liverpool for example), are doing worse than last year. Some of our players have regressed a bit, others have been just as good, and others have improved (some quite substantially even). I care whether the manager maximises the output of his players, and have never said otherwise. I just said "individual brilliance" and "bailing out" are positive aspects, not negatives. Maximizing the potential for individual brilliance and bailouts are (some of the) managerial traits I appreciate.
Yes, we will be bailed out more often than we have been. At the same time though, we'll still have a manager who thinks it's reasonable to ignore the fact that we often have 50 yards between a slow centre half and the goalkeeper. We'll still have a manager that doesn't see the problem with a goalkeeper who doesn't come out for crosses, ie makes it easy to attack us. We all knew that going behind in the first ten minutes would end up biting us in the arses, yet we've been starting games slowly for three months now.
I fully agree we need and upgrade in goal, and at CB. I think most people agree. I also agree that falling behind as often as we do is the opposite of what we should be doing. But then again, I don't really trust Henderson, and we don't really have any good alternatives at CB as of now. Hopefully this will be taken care of in the summer. If we play deeper (reducing those 50 yards you mention), that'd affect our ability to break down blocking teams, and would make us less capable of dominating midfield, and the game in general. I think it's the right approach to push higher up the field, but we need to be better at it (which I think we will be), and De Gea needs to step it up or step down.
So in terms of what's sustainable, it's not sustainable to have a manager that can't analyse the deficiencies of his own team and fail to address them. It's naive to think that our board will sanction £200m of net spend per year on squad improvements. The smart move, economically, would be to get a new manager in who could do much more with much less. And even if the club decides to go with the 'individual quality to bail the manager out every game', is that approach good enough to challenge City and Liverpool with the standard they've set over the past season? Is it good enough to consistently get 80+ points in the league with the current manager? We went from 66 points during the Mourinho meltdown season to 66 points last season, and are now on course for 72 points this season (while on a bad run of form, so probably likely to decrease unless we turn it around quickly)
I'm not asking for £200m net spend per year, am I? But I for sure hope whoever we buy has the ability to bail us out and score goals due to individual brilliance on a regular basis, or improve our defensive deficiencies due to individual traits (be it speed, physicality, skill, or all of the above). Liverpool lost their best individual player, capable of bailing out the manager time and time again. The same manager has kept playing the same style without him, and it has backfired. Big time. They're getting punished heavily for not having full backs capable of defending, now that Van Dijk is out. Individual brilliance is essential for creating a consistent winning environment, and LFC this season is a prime example of just that. This goes for Klopp. Pep, Ole, Ancelotti, or literally any other manager in football.