How many years has a LeBron-led team been the the “best” team in the league? Not as many as you think. You can’t say he was the sole contributor to Miami’s success, and his Cavs teams pre-Miami weren’t ever that elite. So the best team “most” years argument doesn’t even work for LeBron.
Give me the best player in the league on a successful team (not necessarily the best team) for MVP. That’s all.