> There is no consensus about which of 5 workdays to drop to get there
As a company (or better yet as a society), just redefine the weekend as Friday – Sunday, or Saturday – Monday. I don't think anyone is proposing a free-for-all approach where people get to pick and choose which day they take off.
> Enforcing shorter days means that the gap between the hard workers and those who are just showing up for the hours
I have a hard time understanding this mentality. The law and your labor contract only requires you to work 40 hours. Some people may choose to work more than that, but to what end? So you get to feel superior to your coworkers? If the law reduced the work week to 30 hours, would you seriously hold it against people to spend more time at home with their families?