For example a matchmaking service for shared learning goals or interests could for sure be within the power of a startup. Something like 42[0] but without a fixed institution. Or community level organized learning environments for various subjects. Or even to go more in the vien of Papert and Turtle, a npm type system but with a strict pedagogical focus.
There's a ton of systems that can be hugely powerful without depending on a classroom model or a school/institution. And there's no reason these can't be as impactful or more as systems and services targeted towards public/institutional education.