Let me play Devil's Advocate here. I do think better third party support is coming to the Wii -- it's almost impossible that this won't be the case -- but I'm not sure it's going to be the AAA, "everyone abandons the PS3/360 and moves to the Wii" exodus some might hope for, either. Let me enumerate the reasons why.
1) Engines. Companies have invested milliions of dollars into PS3/360 engines, and having now done so, the costs associated with PS3/360 development should be modestly lower. In addition, there is the psychological effect of sunk costs, whether that effect is valid or not.
2) Unclear demographics and marketing. Precisely because of the "Blue Ocean" strategy and Wii's ability to draw in a variety of players, it's often unclear to publishers (who green light titles) what games will or will not work on the Wii. We've seen hits and misses across the board. By contrast, the demographics of the PS3/360 are very well understood -- it's basically the same people who played Halo/Madden/GTA/MGS last generation, primarily composed of 16-30 year old males. Publishers like clear, well defined demographics that they can understand and predict; they do not like making games for an unclear audience with an unclear result. In addition, the marketing firms for these companies have spent decades honing their marketing for the aforementioned demographic; I think many are completely lost when trying to figure out how to market to young girls, for example, or even what they'd enjoy, let alone figuring out how to appeal to both boys and girls simultaneously.
3) Developers. I think a lot of Western developers are not interested in working on the Wii. Many of these developers grew up developing on the PC, and as such, they directly associate better technology/more horsepower with better games. As such, many of them view the Wii as compromising their vision even further than the PS3/360 already do.
If you'd like a condensed version of the above: the PS3/360 sell to well understood markets with well understood tastes that these publishers already know how to market to. In addition, many established Western developers in particular put heavy emphasis on technical horsepower, and would prefer to work on a system with more horsepower whenever possible. The Wii has unclear demographic breakdowns with unclear tastesthat require new marketing tactics.
Many publishers would rather spend 3x as much to produce modest profits on the PS3/360, because there is a 95% likelihood of success. In comparison, the Wii is 1/3 as expensive and has a chance to produce much greater profits, but each individual project may only have, say, a 50% chance of success. Looking at EA as a premier example, they built their entire empire on risk management, by selling racing games, shooting games, and sports games to predictable, stable audiences they understood and can rely on. The whole point of the Wii is to be unpredictable and less reliant on old demographics, so they aren't exactly built for Wii success.
