The problem is that people expect to get the output of 100 people with a $20 subscription by spawning multiple agents. This is unrealistic. I'm using 2 codex plus account and able to manage a repo with 265-300k lines of code.
Human retain knowledge, product knowledge, can pick up more work often for the same money. And having many of them means your business wont go down if provider suddenly bumps API pricing.
Talent and skill is for sure not the reason, coz biggest names now seem to all be immigrants.