If we all had a 4hr job day, then people will be getting 2 jobs. In a consumer markets, where how much you pay for housing determines the schooling of your kid

If we all had a 4hr job day, then people will be getting 2 jobs. In a consumer markets, where how much you pay for housing determines the schooling of your kids, or the "want" for plasma tvs, nicer cars, more shiny things will make people work as much as they can. The only way to enforce a 4 hrs work day will be thru law (goverment mandate not to work more than 4hrs a day, ala EU's 37.5 normal workweek), Or, if something like that star trek machine that can create everything (you press a button, and food just comes out from it, or any electronics/material need you need). Then people will be working only to teach, design new things, entertain, as material needs will be superflous.