You have to bring millions of dollars to the table just to qualify, which leads to extreme risk aversion by publishers and developers, and a tendency over time to lose players who are tired of the same old thing dressed up in more and more expensive clothes. When your game is backed by tens of millions of dollars, you can't use it as a testing ground for wild new mechanics and dynamics never tried before; however, when you're building a low-budget 2D platformer, even your successful experiments won't make an impact on the medium at large, the "big games" that get everyone talking.
What we've got left is a huge gulf between popular, full-experience 3D action/adventure games that need to be financial blockbusters to survive, and marginalized casual/handheld/movie licensed games that don't register on the mass consciousness radar.
We need our B films. We need that freedom to explore truly meaningful new avenues of interaction, quickly and nimbly, without the pressure of an eight-figure budget and multi-year dev schedule weighing down on the whole enterprise. Noir already scouted this territory for us.