To me it just seems that third parties have poisoned the Wii and now there's no going back. To use Capcom as an example they half-assed their initial support. Their best effort was a port of a Gamecube game (which is already playable on the Wii). I think Capcom's typical target demographic has just lost interest in the Wii due to Capcom never giving it that good of support to begin with. Like Capcom? Like Resident Evil? If so what use is the Wii to you? Resident Evil 5 is on the PS3 and X360. All of Capcom's other big games like Street Fighter, Devil May Cry and Dead Rising are on those consoles and not on the Wii.
What demographics is the Wii really ideal for? It's clearly the best choice for kids, casuals and Nintendo fans. The VC is the best choice for classic gaming so it wins there. And it is the console of choice for lightgun games but, really, how much of a market is there for THAT genre?
For years I complained about the Wii's poor third party support and for years I was told to just buy another console. This was apparently the normal thing to do. I didn't like it but I eventually gave in. Well now the Wii is just my Nintendo machine. I don't really pay any attention to anything else. I'm not alone in this. I imagine most of Capcom's target demo is in the same situation: if they own a Wii they also own at least one of the other consoles. If you're a big Capcom fan this is a REQUIREMENT. So why would you even remotely care about Capcom's Wii efforts when you've got a console that has Capcom's REAL games on it?
This is the situation that I think third parties have created. For a core gamer the Wii is insufficient. So you have to buy another console and the Wii becomes a specialized item and thus only the best exclusives (ie: Nintendo first party efforts) are really going to grab your attention. You don't HAVE to put up with anything else so you don't bother. The combo of consoles you have provides enough variety that one need not bother with mediocrity.
So yeah, Capcom is going to notice that their RE lightgun spin-off isn't going to sell anymore because the lousy third party support that THEY were a part of has made it so that most Wii owners that would have been the target demo for those games have now bought a second console and thus no longer need to "settle" for less. They've got RE5 now, they don't need a lightgun game to get their RE fix. They don't need to bother with the Wii for their Capcom fix. The Wii is only required now for their Nintendo fix and, what a surprise, Nintendo games continue to be high sellers.