I'm a core Wii owner, and despite owning a 360 as well, I've found the time to buy World of Goo, LostWinds, Resi 4: Wii Edition, Okami, No More Heroes and Little King's Story. The reason these don't post strong sales (with the exception of Resi) is because they're niche titles. Even saying that, NMH has sold well enough to warrant a sequel.
Perhaps most 3rd party offerings simply haven't had the quality, accessibility and appeal that Nintendo's 1st party efforts have. It's up to third parties to make those kinds of games. I honestly expected more to turn up this year, with so few Nintendo first party titles out. Though the 3rd party line up for the next few months is pretty good, actually.
They may have a tough time competing with Nintendo's line up next year, though.







