I've thought about it as well. It is extremely hard to innovate successfully commercially inside the educational system. On the other hand, targeting the bottom of the system, the individual teachers, parents, students, and the like, does work locally. Scaling that up to something akin to your stereotypical internet startup, however, is hard or even impossible because once you get big you're start messing with the educational system as a whole, looping back to the original problem of entering into the educational system. Still, I think that selling individualized educational services will work, it just does not scale.

(And the question is: should it?)