I'm certain Miyamoto is paid very well, but that he is also very aware that what he wants out of life and his career would not be well suited by looking to make the most money possible ...
As a guess, I would expect that Miyamoto has probably been approached by every major publisher and all of the console manufacturers at some point in his life and offered an obscene ammount of money to work for them; and yet I suspect that he was fully aware that none of them can match what he truely values about his position at Nintendo. Sony and Microsoft would never have let Miyamoto influence their hardware to make systems like the Wii or the Nintendo DS, and almost no publisher in the world would have allowed products like Wii Sports, Wii Fit, Brain Training, Nintendogs, and so on be produced.
