I know what you mean. but I'm also not sure what innovation can be expected from something as utilitarian as an OS. Do you have any ideas of what you'd want to see?
Boot up an old Linux distro from around 2001 and compare WindowMaker, AfterStep, Fluxbox, KDE, Gnome, Enlightenment, and half a dozen others. Compare those to fictional UIs seen in movies, Hypercard, visual development systems like the ancient Klik n Play or modern Scratch or MaxMSP, etc. Learn about OLE (object linking and embedding) and document-centric vs. app-centric computing. Think about all the different ways data can flow between components of a system and how those flows can be grouped differently. Look at alt and historic OSes like Be, TempleOS, SunOS, IRIX, DOS, VMS, OS/2, old UIs like Dosshell, Commander. Look at tablets vs phones vs desktops vs. game consoles vs appliances. Remember that bytes and bits and addresses and instructions and files and programs don't necessarily have to be the fundamental units of an OS.
Then, after all that, come back and tell us that a modern desktop is the utilitarian endgame of OS innovation :).
There's a small, if somewhat contrarian move, especially in the *nix/free software communities, that goes along those lines. You'll find a lot of people fed up with hamburger menus and nondescript icons and widgets, poor API stability (and, therefore, lack of easy scriptability (is that a word?)) and other questionable developments of the more "modern" approach to building desktop systems.
Some of the folks in this camp are firmly in the traditional Unix "camp" and mock cat -v, but there's a pretty refreshing diversity of views there. Some swear by the Unix Haters' Handbook, others come from (what's left of) the Amiga community.
I don't know if there's a central gathering place, but if you look around the Fediverse, IRC, various tildeverse servers, you'll eventually run into someone :).
I want to see a power user OS. Something designed for humans who need to analyze huge amounts of data in arbitrary ways. Something that knows how to work with cloud resources to profile new data sources, simplifying the whole ETL challenge. With great APIs at the program level, so I can always pull datasets between apps, use the best app for the job, and automate everything I need to do twice.
My blog is mostly just tech demos or tutorials with dry writing. I do think about the very deep unmet potential for technology often.
A 1995 book that somehow ended up in my old home town's public library called Tog On Software Design, describing a project at Sun to build a desktop of the future, was one influence as a kid. Definitely check out the celebrity endorsements on Amazon.
On a historical note (and most of it has come to pass, though maybe not in the way they wanted it, and certainly not as "unified" as they conceptualized it), check out the Xerox PARC project that was termed "tabs, pads, and boards":
