It isn't about replacing in person instruction with online. It is about making college courses available to anyone.

At the turn of the 20th century, my grandfather certainly could not afford college. He did what people at the time did who wanted to get a college degree - he took it by correspondence (by mail).

He liked it enough that he started a business selling correspondence courses. He met my grandmother through selling her engineering courses (she was a mechanic for the phone company).

Online courses are just a modern version of that.