Well according to these charts, Nintendo is absolutely dominating the Japanese market. It's the western market that's the real challenge due to pressuring the company to go the way of Sony of Microsoft (microtransactions, sponserships from other companies to advertise their games, edgy titles, etc.). Not even wanted-titles like Metroid, Star Fox, and F-Zero saved the GCN back then, which is what the Wii U is being compared to. Nintendo's fine the way they're on right now, and starting with Tropical Freeze, they will surely drop the bomb in the western market.
As for DS virutal consoles, wasn't it already explained that they wanted to provide more use of the gamepad's mechanics?