As someone who's done a lot of work in e-learning, the biggest problem is making something for subjects that anyone would bother using. It's a lot of energy to

As someone who's done a lot of work in e-learning, the biggest problem is making something for subjects that anyone would bother using. It's a lot of energy to go learn physics so who wants to try it in some half-finished, inconsistent, unverified e-course. Programming is easy to teach because it's all conceptual, and the concepts are clearly defined and structured. So you could maybe teach linguistics in this way, but not something like Spanish. Or if you tried to have a collaborative Spanish curriculum it would be a huge effort to collate everything into a logical progression ("they don't know that grammar rule/word yet") so you might as well pay someone to write a consistent one from scratch. Same for physics/math/any open-ended science or humanities class. Your second big problem is getting anyone to actually contribute a lesson plan in a way that is consistent with the format you're trying to structure things. People aren't going to make one from scratch for you, for free. So you either pay people or accept all manner of half-baked, duplicate lesson plans.