If the US didn't have overtime rules and required health care for full time jobs, people could work just a single job if they needed to work more hours to make ends meet. They would save a lot of time on commuting especially since many poor people use much slower public transportation to get to their jobs. They would also probably have more reliable schedules. Having a society that people only need to work 40hr/wk might be a good idea (hell, why not the 4 hour work week while we are at it) but the current system encouraging that seems to have failed.