Earlier quoted context omitted.
"They hired just about anyone and paid crazy rates" I don't think this proves your point. Just hiring someone to do a job does not equal teaching them. Teaching means not only practice, but also well constructed feedback and sufficient time and space to learn, and to learn from ones mistakes. Kludging an ASP application together after reading "learn ASP in 24 hrs" does teach something, but there is so much noise that…
Back in the late '90s through the dotcom boom, we were teaching ourselves as we went. There was a running joke about HR looking for "someone with 10 years experience with HTML". In the mid-1990s, I was working on data transport stuff that involved hand-rolled socket code and daemons in C, and parsing the data stream in lex and yacc. We didn't have Apache, or ssh, or xml. A few short years later, I was working on real…
"If someone can teach you how to do something, it's already mainstream."
I don't think collaborative learning should be undervalued, though. There are several colleagues without whose example and input I would be a much worse programmer. Not in technical details, but harder to define things, like attitude that leads to success and how to make designs simpler.
'Mainstream' does not mean obsolete. Reading and writing and Roman alphabet have been mainstream for centuries, yet people utilize them with an amazing variance of productivity and value.