People working 4 hours a week still have to pretend to be productive for the other 36 hours though. They still have to sit through meetings, and justify their time, and answer Slack messages, and have reviews. They're not free to work on their own projects - they're just 'not working'. That sounds far worse than spending time working on something you actually care about even if it's not your own idea.
The comment that kicked this off was “ If somebody wants to pay me $300k to work 4 hours a week, I'll happily take the deal. As long as that's the actual acknowledged situation and not "most of your job is pretending to work and making people think you're important"”