Development teams for the Wii will always be smaller than a big budget game and will often be working on a shorter time table as well.
In short, it simply takes fewer man hours to produce the game resources, of which programming code is now a much smaller portion of a game's overall effort.
Art resources (textures, models, etc.), sound resources (everything from soundtrack to SFX to voice acting) eat more budget funds in terms of man hours. More artists, not more programmers is the norm for high budget games.
It goes without saying that story and writing are typically the most neglected aspects of game development which is reflected accordingly in the budgets of most high profile games. It has been changing, but in most cases, still holds true.
Someone's going to have to dig up some developer quotes, but generally, it's been said that the budgets for Wii games are typically as low as a fourth of the budget of a PS3/360 game. Naturally there will be quite a discrepancy depending on the games being compared.







