> They are just straight up delusional, no?

Well, I guess that's one way to put it. Another is "dress for the job you want", startup culture typically seems to shove people in the direction of "aim big and believe in yourself, regardless of what others say" so naturally you get these companies who seem very disconnected from reality.

I'd also wager a guess that the amount of money makes people's reasoning and perspectives get very messed up as well, for better or worse.