I read "drop-in remote worker" as AGI. You can give it any task and it performs at-or-exceeding human level. The real question to me then becomes the implications for the rest of the economy, not simply a question of what happens to vertical AI companies.
So many B2B tech companies exist to make the work and organization of humans easier. Is Github still as valuable if the vast majority of code is written and reviewed by AI? What about Slack, Linear, or Salesforce? And that's just starting with tech.
If there are relatively few humans in the white-collar workforce, then we are talking about nothing short of a complete remake of the economy.
In my opinion, the article spills a lot of ink trying to prove something that to me feels obvious (given that you accept the premise that one day soon we will have AGI) and very little exploring implications beyond this narrow perspective. Perhaps that is coming in future chapters.