Why build a team when you can win titles?
Is Lewis building Mercedes? No, as far as I'm aware he's brought no one to the Mercedes team, doesn't have number 1 status and doesn't have much of a say in what Mercedes do.
Schumacher went to Ferrari and key members followed, and built a team due to having number one status.
Not sure where all the hates coming from, he's proved himself in cars that weren't front running cars, BMW and Toro Rosso for more than one season. The Toro Rosso might have won a race, but it was for one race only the rest of the time he was in the midfield and proving himself with some great drives other than Monza 2008.
Not sure why I'm defending the guy, I don't support him and his results have done the talking, yet somehow he's lacking in a new area when he proves doubters wrong in something that he was criticised in before.