I got really into computers in the mid-late 90s by which point we were mostly down to Wintel and Apple hanging on by a thread. What I remember from that era is that nothing was compatible with anything else. It took a lot of work to interoperate between two PCs, let alone cross the gap between OSes. So for a long time, I have kind of taken the current world of few OSes that are highly interoperable as being a great t…
Yes it does have a couple of nice ideas, and it was much better to use than Windows 3.x + MS-DOS, but that is about it.
All the UNIX based OSes that I really appreciate, have moved beyond it, namely NeXTSTEP, Solaris/NeWS, Irix, Plan 9/Inferno.
Thankfully only BSD and GNU/Linux are stuck into being a continuum of UNIX clones without much to add, when you see their conferences it always boils down to kernel features or filesystems.
GNU/Linux has the ingredients to make an Amiga like desktop experience, with D-BUS, GNOME/KDE, but the fragmentation and love for POSIX CLI applications just doesn't make it worthwhile to try to make it work.
Look at iOS, macOS, Android, Windows (UWP), GenodeOS, Fuchsia, Haiku, Azure Sphere for the pursuit of modern ideas in OS research. The fact that some of those have a POSIX like kernel (or deeply customise Linux kernel) it is just an implementation detail of the overall architecture.