He's been saying repeatedly that "it's going to be fully self driving next year" for the past 6 years now. At what point for you does that change from "overly optimistic prediction that didn't pan out" to "he's likely lying through his teeth"?
The unsettling duality that Tesla fans will accept is that somehow Musk is both an unrivaled genius AND he's consistently betting incorrectly on Tesla's timeline for L5. When other self-driving experts in the field indicate full L5 for the industry is probably a decade or so away (optimistically), I'm not keen to believe that Musk is just blinded by pure optimism for 6 years running.
Sure his talk was dumb and a lot of people fell for it, but that's just how marketing works.