You already took that 20% pay cut. Our pay hasn't gone up with our productivity in decades. According to Keynes, we should have been working 15 hours per week by now. We're not, because we're not reaping the rewards of our work. It's all gone to the rich. That is the big thing we need to reverse.
I'm working 4 days a week, and that's working very well for me. So is my wife. So is my brother, and are several of my friends and coworkers. I strongly recommend it. We should be demanding better, and not discourage each other by saying it's absurd to want a better life.
Of course you're entitled to a better life, a great life. The "absurd" part comes from the expectation that an employer is just going to wake up one day and decide you don't need to come in on Fridays (or whatever 5th day is). Perhaps you can arrange a 4x10 schedule or, as I stated, take a pay cut -- that's great if it works for you and for the employer (or maybe you don't have an employer). But the OP was seeking a "free lunch" -- less work with no reduction in pay. Further, the OP's expectation of how the 5th day would be spent is, in fact, absurd. Americans already have a lot of free time, and most of it is spent watching television: https://www.cdc.gov/pcd/issues/2019/19_0017.htm, https://fivethirtyeight.com/features/heres-how-americans-spe...
I think most people spend their free time watching television because they lack the will or energy to do anything else; work has sucked it out of them.