I think the author's point is that each type of job will basically disappear roughly at once, shortly after AI crosses the bar of "good enough" in that particular field.
I'm willing to believe the hype on LLMs except that I don't see any tiny 1-senior-dev-plus-agents companies disrupting the market. Maybe it just hasn't happened "yet"... But I've been kind of wondering the same thing for most of 2025.