Self education is all around us. Many peope teach themselves things all the time. It might not always be formal education but it’s still education. Over the years, through much reading and trial and error I have become a pretty good gardener, without any formal education. Many people learn trades without formal education. A carpenter, plumber, electrician, roofer, painter, etc can be taught by example or even just by reading books and some practice. I know it’s not college level education but it certainly could be expanded to that. You might need a license or degree for many jobs but some of these requirements can be gained by testing.
Another example. I taught myself the information necessary to pass a couple HAM radio licensing exams. No one showed me/taught me. I took it upon myself to study the material and ultimately pass the tests. Many auto mechanics are self taught. Now later on they might get specialized training but many times they pick up things in other ways.
There are many examples of self teaching out there. Am I going to be a self taught doctor? Probably not. Could I be a self taught accountant? Maybe.