Is that really a good reason to sell a player though?! It's like people suggesting we sell Giggsy at the same age just because he was still inconsistent...it's frustrating for sure but we're lucky to have these players in the first place, you don't just throw them away over something like that. People talk about Giggs not going on to be the new George Best and Rooney not going on to be better than Ronaldo but the reason for that is that lack of single-mindedness and selfish focus that the very top, top players have - that's something that held them back as individuals but it's also something that benefited us hugely.
Can you really see George Best playing left back (like Giggs multiple times) or Ronaldo playing as (essentially) a left wing back (like Rooney v Barcelona and co.)? Think about how many different roles Rooney has played here - in behind Van Nistelrooy, in behind Saha, ahead of Tevez, on the opposing wing to Ronaldo, up top on his own, in centre mid...and each time it was to benefit the team rather than in pursuit of his own selfish goals. Giggsy's the same in that after being voted YPOTY two years running, he's moved out to the right wing to allow Sharpey back into the side. Not long after that we have a long-term striker crisis so he plays as a striker. Fast forward a decade later and Scholes is out with the eye-injury so he reinvents himself as a centre mid and now, at 39 years old, he goes back to being a winger at a time when our wingplay's the worst it's been in years.
The number of times Rooney and Giggs have put the good of the team ahead of their own selfish goals is remarkable for players with their level of talent. It might stop them from being up there with Pelé and co. as individual players but it'll also lead to them being Manchester United's record goalscorer and record appearance-holder. We're lucky to have a player like Rooney and unless he wants out the door I see no reason to push him out. Otherwise we wouldn't have fought so hard to keep him in the first place.