When it comes to home console gaming, what Nintendo did was raise the bar to a level that exceeded the expectations of gamers and made games exciting again. It was the difference between having a single person crank out a new game every month versus having a team of people work on a game for several. With the nature of the arcade, games could only be played for a few minutes at a time without requiring more credits.
I think Nintendo saw that it would be possible to put a larger budget into their games and still profit. If not for Nintendo, that isn't to say that Miyamoto wouldn't exist, right? So maybe Mario would belong to another company. :P