Slavedemonxi, the problem is 2 fold.
1. 3rd parties ignore Wii so gamers that would normally buy 3rd parties ignore Wii.
2. 3rd parties finally give Wii some love but find not many receptive after being screwed over for so long.
However, the user base itself is growing in such shape and proportions that 3rd parties will have no choice but to start taking it more seriously.
But you're wondering why given the huge install base do the games not sell so well yet? Largely because the Wii version is usually an after thought. Poorly handled by an outsourced party and given little to no publisher fervor and marketing over the HD versions. If the publisher puts to little love into it, so little love will be given from consumers....metaphorically speaking.
When a multiplatform game leads development on Wii or is at least marketed just as much as the HD console iterations, the sales will show it.
If you'll note that ever franchise with multiple Wii entries is seeing marked improvement in sales for the latest entries. Each have the benefit of long sales trails on Wii such that EA sports games, CoD: WaW and others will all be million sellers. Something not expected from Wii from publishers, analysts and the media for the first year or so the Wii existed. Look at last generation. Madden 08 already outsold any Madden game on GC. CoD 3 outsold all the CoD games on GC. You get my point.
As the sales continue to increase, 3rd parties will put more effort into their Wii development. Not so much at the expense of the PS3/X360 but just to get a bigger chunk of what they've been missing so far.
The rEVOLution is not being televised
