That's a strange way to describe research and experimentation (though not strictly incorrect).
>I just wished they focused on making the mainstream better
Plan 9 predates all of today's mainstream operating systems.
Many of the modern OS research papers that I have read take an existing solution and mess with it. As an example, many file system papers take ext[34] or btrfs and do something to them (if we want to debate this statement, we can). I see this with replacement algorithms, packet schedulers, etc. Much experimentation happens but it is usually in the context of Linux or FreeBSD or some other popular existing solution these days.
There are papers that buck this more conventional approach like barrelfish and singularity and exokernels and L4 etc. etc. etc.
I do not think they are the status quo and I am/was not saying that plan9 is a bad thing, let me be clear on that.
>Plan 9 predates all of today's mainstream operating systems.
This is said with enough certainty without being true that I am allergic to it. All? Plan 9 started in the late 80's [1] OS X/iOS is a mach derivative which is circa 1985. The NT OS/2 project which begat modern Windows was started in 1988. BSD? All descendants of BSD which first released in 1977. Rob Pike complains about BSD's "cat -v" in the early 80's.
Maybe you are using "predate" with a different connotation but I don't know which. At the very best* it co-existed with the others.
Everything you can do with Plan 9 you can do with any other system anyways, only it's marginally more tedious. If people can tolerate that, that's alright with me. What should I care how the masses do their computing? Why should I pester people about it? I don't go around arguing to people how great it is to be a pro-skub star-bellied sneech who eats their bread butter side down. Operating system evangelism and holy wars are older than the internet, and I have become very tired of them.