I read the first half and skimmed the second half because the author couldn't make a point somewhere in the giant wall of text. Even if there was a point in there, the subject is too broad which is another question I have...
Anyway, in a broad (meaningless) rebuttal, I wouldn't say EdTech has failed- everyone I know has learned how to do something real they didn't know how to do before from youtube. Easy examples: basic plumbing, basic electrical, playing guitar, playing drums, systems design, how to improve in their sports, software stuff... even my dad learned how to properly put up a gutter on their house recently.
What I'm observing it seems like people are learning more its probably just schools getting in the way.