I agree with you. For now Man United is no longer a scary team, although they have a lot of great players but their performance doesn't look good. Their Teamwork is less effective and they don't have a good defense, luckily they still have a goalkeeper like De Gea, without him it would be very easy for other teams to score goals. With great players, Man United should be much better than it is now but in fact, their performance is even worse. So it's clear that Man United has a pretty serious problem, it either there is no good synergy between the coach and the players, or indeed the strategy the coach has is not reliable.
They are scary team for their fans because their fans can not predict what Manchester United players will perform in next matches. They are fluctuating so much between good and bad matches and are playing like Arsenal 2 or 3 seasons ago.
There is no confidence in Old Trafford and their player mentality to contribute for the club is broken. Without good attitude, good psychology, it is super hard for them to come back. They have systematic problem so any star player can only help them with short term effect. From Bruno Fernandez, Maguire, Cavani, Greenwood, Ronaldo, Pobga, De Gea. They all can not carry a whole team because it is hard to see a whole team can play well together.