Is he saying that $50k/year far outstrips what he can reasonably expect to earn as a fintech dev? If so, he's at least as much of an outlier as the $500k/year folks on the other end.
For better or worse, HN is a SF Bay Area centric forum. U.S. centric beyond that. All the discussion of whats normal needs to be understood through that lens. It's the digital equivalent to coming to SF and saying $50k/yr is crazy high. Sure, but not where you're standing/typing to.
(I'm not saying $500k is normal, nor that his other statements are off)