canvas2d IS hardware accelerated too, or at least it does not mean software rendered, in fact, on chrome (I think C2 has things to prevent that) software rendered enables a simulated WebGL (since it is software rendered, there is no limitations feature wise, however it will be slow as hell), and believe me, I have actually a netbook with software rendering by defaut on the chrome browser, and you will not go over 10 fps on it, even with very few elements being displayed.
the fact canvas2d outweight webgl can come from various factors:
-effects, but since there are ways to disable them no game should be blocked by that.
-perhaps a webgl implementation of the browser that is woncky?
-updating text objects too many times and updating them, they are not performing well on webGL, not sure of the reason.
-using r0j0h0und canvas plugin, it does not render directly in the webgl renderer.
I might forget some (or just don't know them), but the point is canvas2d is another renderer, that is still hardware accelerated.
Game design is all about decomposing the core of your game so it becomes simple instructions.