And, it doesn't.
I'll be quick to change my tune when online education proves itself effective - but right now online k12 education is failing miserably all around the country despite great promises and powerful support(e.g. there are current 16 online k12 charter schools in Pennsylvania getting terrible results).
This isn't a field in which innovators are allowed to fail for a year until they find appropriate answers to their problems - that year of failing is a year of their students failing to advance. There is no stomach from teachers, administrators, or parents for such bumbling - nor should there be.