I have no doubt that JM could do a lot better, and be a lot more positive - but so could the board.
Lets face it - they ***** up over Perisic last summer, and all season that side of attack was dreadful (not helped by the aging and useless Valencia), they have also ballsed up this transfer window by acting so slowly and penny pinching here and there. Lets not forget that City have spent near enough the same on Mahrez (a backup) than Utd have in total so far ....and 1/3 of that is on a 20 year old kid who very few even expect to be starting before next season (regularly).
Its not all about spending but when City have spent £500m more on transfers in the last ten years (figures were widely published a few months ago) it was only a matter of time before this scale of dominance happened. They are also bringing in more mature players who are coming into their peak - no disrespect to Rashford, Martial , Lingard and a few others but they are all very inexperienced and form can be very shaky at times (I know Lingard is considerably older, but given injuries etc is still pretty inexperienced at this level).
The fact that Liverpool have also spent at least double this summer than Utd so far, and have (from the outside at least) had a pretty easy / uneventful window (I suppose Fekir but impossible to know truthfully if that wasn't a bit ***** by both sides, and transfer still could happen) just rubs salt into the wounds
The result the other night doesn't mean a thing in the context of the season, but it doesn't help at all that 1/2 the senior squad isn't going to get a decent pre-season at all , and will probably miss the 1st two games at least (and the 3rd game is vs Spurs so not the best game to come back into in all fairness).
JM deserved another season after finishing 2nd , and deserved to be backed fully by the board this summer (there shouldn't be any necessity to sell first before bringing new signings in - especially given how the window is arranged this summer, but it certainly suggests that's how the board want to operate) , so I can understand why JM is annoyed (2nd summer in a row).
Its also hard to tell because we are missing so many of the 1st team how this season will be, but there is no excuse for JM to maon about the kids, he should be fully supporting them and that's not on at all. Periera is looking really good in a new position after his two years in Spain on loan, and looks like he will be starting a few matches given Matic's injury. Impossible to know about Fred given he only got 15 minutes the other night.
The board have left it too long (this summer) to sack JM, even before considering there is no-one at all at even remotely the same level to take over - I don't see any reports of unhappy players though (even if they have a right to be, esp the younger ones) but wouldn't surprise me if this starts given what he has said recently.