Real answer:
Russell, because he is the league's greatest winner. Also, because he was so innovative. First black coach. First black leader of a team. And a major advocate for civil rights. And he was also one of the greatest rebounders and defenders ever.
Bird and Magic because besides the talent and accomplishes, they led the NBA out of the disaster that was 1970's basketball with there being two leagues and rampant cocaine and other drug problems affecting the game. They saved basketball. Ratings soared, as did revenue and basketball overtook hockey and baseball as the country's 2nd most popular sport. All because of Larry and Magic. They were that influential.
Then, of course, Michael who took everything from Larry and Magic and built on it. He also became the best player ever. The greatest shoe salesman ever(after Bird and Magic started the basketball shoes revolution and branding). And a culture changer.
Those are your NBA Mount Rushmore players, because reaching those heights means more than just counting stats.