[AnIdiotOnTheNet]

In theory most AppDirs could be run on a normal linux distro with a wrapper script and a package of the base system libraries if certain choices were made (like using wayland instead of a new display server). I'm not opposed to practical compromises, but part of my design goal was to get rid of legacy stuff that doesn't make sense anymore (like the way UNIX handles the file tree) and build a better (and simpler) mousetrap where it was reasonable.

I disagree that it needs to have its applications be runnable on Linux Desktop to work. I think that if you build a system people actually want to use then the applications will come. After all, Linux is a tiny percent of the desktop using population and it still gets targeted just because people are getting kind of sick of the behavior of the companies behind the proprietary OSs. Imagine if people actually wanted to use the Linux Desktop instead of just put up with it.

I think compatibility in the opposite direction is much more important. Like how MS included an XP VM in 7, or Apple included a MacOS Classic VM in OSX, the new system could offer ways of running "legacy" Linux applications to make the switch easier (also Windows via WINE, though with a much lower success rate, and possibly Android via something like Anbox).