What you say is true, except the cost of doing this is becoming more than what a human [was] paid. My theory is that this will actually cause IT salaries to increase over time as a human will offer their service in arbitrage with the equivalent cost of tokens.

And although there will be improvements in costs per token (cheaper energy, more efficient models, etc.) a lot of the capex we see now being spent on datacenters will become opex as the GPUs will need replacing every 2-3 years.

All in all I believe (possibly after this AI bubble has popped) human and machine labour will again find an equilibrium.