You said, some rich club will pay over the odds for Rooney in two-three years time, regardless of his form. I disagree with that.
Rooney doesn't strike me as someone, who will work on his fitness diligently in order to ensure his career longevity, like the likes of Lampard and Giggs did, for example. He's got the last contract of his career and I fully expect him to start taking it easy in a year or two.
Given his wage packet, attitude, fitness issues and age, no club will go anywhere near him in three years, let alone pay over the odds, like you said. He won't have any resale value.
That doesn't mean, it's not a good deal for United, given your current situation, of course. Currently, he's still one of your best players and is essential to your club's ambitions.