Miyamoto didn't need to say it. Neither did Reggie.
The games industry isn't an idea, it's an equation.
It's simple: games will be developed and released where they will make the highest amount of money possible, period.
There is no debating this. There is no counter argument. The bottom line is profit.
If the Wii attains the highest userbase, then it DEFINITELY wins. Hands down, no question. The Wii is already the cheapest to develop FOR, meaning that a company will have spent less initial investment right off the bat because HD isn't required. If a 360 game costs $500,000 to develop and a Wii game costs $250,000 to develop, then that company will see that as an immediate $250,000 profit by comparison when it comes to deciding which console to dev for.
When you factor that into the MOST pertinent equation of "Which console will it sell the most copies on?", it's almost guaranteed to make more money on Wii, especially if it has the highest installed userbase and therefore the highest potential for sales.
So you see why it's silly to worry about this. After the barns are swept out, 3rd parties will have no choice but to develop for the Wii because it's where the money is.