I doubt there is a soccer team on the planet with the combined talent of Manchester United. That's what money will do for you. My grandmother could probably coach them to a UEFA championship, and she's dead.
Aston Villa is different. They have significant talent, though not the depth of talent of MU. Jon Carew is probably one of the best players in the game right now. They're a good team, one of the six best in the Premier League this year. On the team roster, they're a match for Liverpool, Chelsea, Everton, and Arsenal.
I've watched them play quite a few matches, and I see the same thing every time, to a greater or lesser degree. Last night I watched the second half of the match with Bolton, which ended in a 1-1 draw. The Aston Villa players have a tendency to wait for the ball to come to them. They are not good about following up balls or getting to an open area of the field. Again and again, you will see a pass come to a person with two or three defenders within a couple of yards of him, because he's standing there waiting for the ball instead of going to the ball.
This seems to be a character trait of the entire team. They are consistently outplayed by less talented teams who display more hustle. Jon Carew was especially bad in the Bolton match - he was phoning it in.
They look tired. The match commentators have said many times that Aston Villa has played fewer players this year than any other team in English football. Maybe they lack the bench depth needed to give the first team an occassional rest. I don't know. But they certainly seem to lack motivation. And that, in my mind, is the fault of the coaching staff.