It is a thing. I don't think any online course can beat a good teacher in a small classroom, but online courses can take you a long way, and are wonderful for t

It is a thing. I don't think any online course can beat a good teacher in a small classroom, but online courses can take you a long way, and are wonderful for the broad variety of courses available. YouTube recordings of university lectures are also very useful - MIT has excellent courses available for watching. Self-learning is not suitable for everyone, but if you have discipline and the ability to understand how things fit together in a subject, it can really work.