Tell that to Alcaraz. This whole contract stems from the fact that Moyes wanted to tie him down forever.
Moyes wanted to keep him as opposed to Ferguson kicking him out the door
Rooney wanted to stay more under Moyes as opposed to not wanting to play under Ferguson again
Far more costly to replace Rooney than lose him (even with Mata, we would require a top class forward between RVP and Welbeck).
That's why I was so annoyed when we lost Mata for straight cash. For all the reasons you've stated, it was pretty obvious then that Moyes saw Rooney as a United player and wouldn't be letting him go.
As for Alc, I don't really get your point. We can't know if Rooney staying is a matter of him wanting to, the club forcing him to or simply because of a lack of serious offers. It's possible that top European clubs couldn't afford him, or didn't want him, but we can't know that. All we know is that Rooney will be a United player for the foreseeable future and that is that.