The Most Valuable Player award is given to players who give their team the most value on the court. I think the award's name is a bit misleading. While it is often true that those who win MVPs do land among the league's top value players, it isn't the true deciding factor of having the most value.
The best way to measure who in the NBA holds the most value for their team is to ask yourself; Are they untouchable?
Being untouchable in the NBA can mean two things: You have a no-trade clause in your contract, or your team would never consider trading you, no matter the offer.