I understand where you are coming from. But you have to keep your mind open for the possibilities that might arise from these additional gamers. Games like Boom Blox probably wouldn't have thought of if not for the Wii. Games that use the balance board like We Ski and possibly SSX if they make another one, have a lot of potential. I also think it could be used for racing games (as pedals) and other things, and not necessarily for health genre games.
I also think it's important that many PS2 owners never played a big name series. If you add up the highest selling entry in the biggest name series, there's still a good amount of users that never played games you might like. And that's assuming that everyone who, say, bought GTA3-SA never bought Final Fantasy X. Or all the people who bought GT3 never bought Need for Speed: Underground.
How about the almost 2 million users who bought Scooby Doo: 100 Frights game? A game which got around 70% score. Do you agree with their gaming tastes?
Just remember that it's expanding the industry, not shifting the industry. Bigger industry means more money in it, meaning that developers can hire more people to work on a variety of games, but it's not going to steal development money. Actually, I'd be more worried with the ever increasing cost and development length of games, because one bad game could kill a company, or one unexpected event during the programming cycle could cause long delays, eating up money and time, which would reduce the number of games available. It also reduces innovation because companies are afraid new IPs might fail, so they stick to the same old stuff.
