as ai becomes an actual replacement for workers, costs will rise to what you would pay a worker, and $6T will be easy

If everyone loses their jobs there will be no demand for the products and services those workers used to create.

A perfect ouroboros.

What about the part where workers take less money?

Except that it would be priced based on pass-through prices rather than existing value perception. It used to cost hundreds to send a letter on horseback, it costs pennies to send an email, consumers aren't going to tolerate spending hundreds when they know it take pennies to send.

Models are getting cheaper, and more efficient, but I don't see how they cross the threshold of full autonomous intelligence in the way that an employee needs to be fully accountable for their actions.