Children are naive, and it's naive to think that we'll get 60 million for Wayne Rooney with 18 months left on his contract, at the age of 28 and shitloads on wages.
Mata might be a bench-warmer, but unlike us, Chelsea can afford to have him there. He is on a longer contract and is younger.
If you think 37 million for Juan Mata is so outrageous that we should put price-tag of 60 million on Rooney then you can't have seen Mata played, at all.
That or you think we should let Rooney run down his contract and sign for whoever he wants for free.*
* Assuming he does not sign a new contract.