It's very easy to say that nobody should have more than 4x the wealth or income of anyone else, but every time anyone has tried anything like that, the unintended consequences have been disastrous.

For example: suppose I'm a musician, and I write really cool songs. My income is maxed out at 4x, and you know, I like writing songs, but eh, it's also hard work. You want me to write another song. How do you get me to do it?

Heck, even if the max is approached gradually (e.g. with income tax that gets increasingly close to 100% additional income the closer you get to 4x), if I'm already at 3.92x, how are you going to get me to write that song?