Fewer jobs, less money --> people less willing to pay for anything more than bare minimum --> downward pressure where being cheap is the biggest selling point.
The thesis (pre-AI) is not "fewer jobs, less money."
It's "more productivity, more money → higher land rents → upward pressure on everything → higher floor of economic productivity required for someone to earn a plot of land to live or work upon"
It's "more productivity, more money → higher land rents → upward pressure on everything → higher floor of economic productivity required for someone to earn a plot of land to live or work upon"