Well you think is just a financial outlay.But by bringing Ronaldo to the club they made a record in selling jerseys,they got a lot of followers and a lot more people watching Man Utd.Thats all money you maybe dont see it but from other point of view he is bringing them lots of money and for his quality he already gave some important wins since he came this summer.
He will certainly score a lot of goals, and he will certainly sell a lot of shirts, and he is certainly - at whatever age - a statement signing. I just don't think he's the answer to their problems, and is not the type of player to turn them into a team that will challenge for the league title.
I certainly not saying he's a bad player, his record speaks for itself. It's just maybe not the best way that could have spent the money.