> This is trivially disprovable. Did grocery stores increase the wages of their clerks once self checkout was a thing, or did they keep wages the same and lay o

> This is trivially disprovable. Did grocery stores increase the wages of their clerks once self checkout was a thing, or did they keep wages the same and lay off some of them? That doesn't disprove anything. Productivity is an input to and has an effect on demand, but it's not the only factor. It doesn't need to be the only factor to matter. Lots of things matter. Economics is a complex field.