I don't see this as that big of a blow to Wii.
1. these games are being released for a decaying home console and a somewhat unpopular handheld: the PSP version shouldn't have too much affect on Wii, the PS2 version might have some effect, but I don't think it will be super-huge.
2. Wii will probably offer more games
3. Wii also offers games from several other consoles