>What is the explanation for that historical fact? Or is it merely a
>fact, and expectations are based merely on the premise that what has
>been and is will be? (That is a good rule of thumb, but subject to all
>the hazards of any rule of thumb.)
Relentless commodification of everything - and as Ursula Huws argues, the commodification of the domestic sphere has been a rich playground for capital over the last century - means more paid workers. It's been a while, but I think Marx writes about this in the Grundrisse (how machines presuppose masses of workers, etc.).
Doug