I have been working 4 day weeks for a decade or more. It is good but it is not like what you are advocating.
Every other week is a 4 day week, we get every other Friday off. They call it 9/80. You still work 80 hours every two two weeks but you only work 9 days, 9 hour days except the on Friday we work 8 hours.
For many people this actually was a reduction in work hours as we often worked more than 8 hours a day under the old rules.
To try and keep up factory output we had an A track and a B track that took alternate Fridays off so that we did not shutdown just worked at half staff on Fridays.
Yes, having a couple extra days off a month is nice.
That is less of a change than the 40 hours pay for 30 hours work you are selling but I think that story is transitory. For an existing worker it is an immediate 20% boost in hourly wages but that is not the case for a new hire and could be eroded over time for the existing worker if is diminishes pay raises.
Actually a lot of people are not working 40 hours a week for a single employer, they get whatever hours they get scheduled. Actually 30 hours a week is often consider full time work. Under the ACA, employees who work 30 or more hours per week are entitled to health insurance; however, beyond that, companies may set whatever standard they like for full-time compensation and other benefits.
Many production environments desire to run 24/7 and only idle a production line for maintenance. That is 21 ea. 8 hour shifts. How about stores that are open 24 hours a day.
I would guess that you would suggest that overtime rules should apply for work over 30 hours a week. What about people who get double time for working Sundays and holidays? Still only get double time for Sundays or holidays?
I worked for years in an environment where the workers craved overtime and fought each other for it.
TEK