If by most, you literally mean > 50%, sure. But I've heard it quoted that knowledge work in advanced economies is something like 40%. So, we are still talking extremely large numbers.
OK, but look, again, if you take away a good chunk of the money that goes to employing people — that is what you mean, right? This money is lost to the labour market one way or another — then don't they buy less stuff because they have less money?
It's the same as if you had taken half their jobs and forced everyone into underemployment through job sharing.
Your formulation forswears them finding replacement jobs because the money will have gone to AI companies instead, and it necessarily implies people having less money to spend.