Seriously. There wide areas of knowledge -- not everything -- that are just are now available for the taking. Mostly technical, but lots of other stuff too. There was a time when, if you were a fan of some genre TV show, you'd have to buy some small press book to get an episode guide. Now there are legions of fans who put it up on Wikipedia or specialized sites.
Mind you, effective teaching is still worth paying for. There is a difference between having a C++ manual and some lessons on a website and having a teacher guiding you through the process and fellow students to work on projects with.
And then there's training. Learning how to use tools, and craft and artistic techniques. You can't grab that off the web. You need a real teacher.
But the kind of things that mail-order lessons taught . . . that kind of stuff you can just put on a website.