I think nobody tries because everyone knows there’s a gigantic chicken or egg problem. Everything is written for Unix-like systems (or Windows which is not tha

I think nobody tries because everyone knows there’s a gigantic chicken or egg problem. Everything is written for Unix-like systems (or Windows which is not that different) and everyone is not going to port all that software to a significantly different paradigm. So even if a new OS was great, the suspicion is that nobody would use it because no apps. In reality I think good compatibility libraries could bridge the gap, so it would not totally be futile to try. But you’d need those compatibility layers out of the box. Another big ugly hairy problem is hardware support. Existing OSes have vast libraries of drivers all built around POSIX-like paradigms. Getting good hardware support on a new OS is going to be a ton of work, maybe more than the OS itself.