An interesting idea. The problem that many part timers have today is a lack of insurance, ability to pay housing and food costs, etc. Shorter work weeks would be better for our health and probably our environment, but there's also the cultural issue that Americans tend to equate having time off with being a horrible person, and of course, if the government got involved, people would be howling that someone spent an extra penny on food they didn't approve of or didn't look downtrodden enough or something.
I think the part time revolution has already come. Full time employment is getting harder to find. A lot of people are scraping by. You can downsize consumerism, but you can't downsize the need to live indoors.