There's a huge distinction between reviving the spirit of Plan 9 and reviving the ideas. Trying to retroactively revive the direction of an experimental early-90s OS to intercept 2020-era hardware is goofy. Computers are very different now than they were then; surely some of the things invented in the past 30 years might influence OS design?

The thing that still appeals to me about Plan 9 as a concept - is the willingness to do a clean-sheet design and not be bound by the way that everyone else is doing things.

A better design would also not fetishize uselessness. It's one thing to have a cool environment but it's quite another to point-blank refuse to maintain a compatibility layer that allows people to run significant programs that people want to use. Plan 9 didn't have to allow the APE (ANSI POSIX Environment, a project from Howard Trickey) to run down into uselessness.

There are a lot of interesting system design questions that arise from letting people use computers the way they want to, for 2021 workloads. I think we probably know how to let people use shell, ed/vi/emacs/... and cc to make hand-built astronomy databases and manually paint a time of day clock into a window. But you don't get to find out the demands of modern computing without having enough compatibility layers to let someone run a database or a reasonably-complete 3D engine or a web browser on your system.