Lot of people misunderstanding. This isn't like a capcom situation where they will only make games that sell over 2 million, it's more of a matter of them making games that will sell over 2 million so they can recoup the costs of the games that don't quite break even.
This. Miyamoto says this in the very quote quoted.
There will be big hits somewhere in our business, and they support the games that fail and allow us to take on other challenges. So our basic premise is to create software that will sell in the range of at least two million units.
To me that suggests that success will fund passion/experimental projects.
The two million mark allows them to be flexible, it is about being cost effective. Not completely going all in, but enough to make solid, well made, fun games that are practically profitable out the door. Profit!