> What this meant was first, you couldn't run stuff like a web browser on Plan 9 (and you still can't; please no-one write to inform me that some dweebish half-assed attempt at a web browser is a solution)
Granted, at the time it was possible, however that didn't fit into it's philosophy.
Notably, there was a way to interface to the internet -- Plan9 has a filesystem for exactly that purpose, all that needed to be written was the frontend.
Like you say, it was possible at the time the decision was "made"; we're talking about duplicating NSCA Mosaic circa 1993, not Chrome.
And in any case, it wasn't necessary to write a web browser from scratch. What was necessary was to support a "normal" side environment to run POSIX, gcc/g++, etc. This would have been a fair bit of effort, but if it had been done (a nice first stop would be to have avoided gratuitous incompatibilities, like "ken c"), the OS could have supported programs not written at the Labs (and a tiny number of other places) and been an actual daily driver.
I write this out of frustration but with a lot of positive feelings about Plan 9; I would have loved to see it thrive. The gratuitous incompatibility made it almost immediately a museum piece, as did the fact that many of the intriguing-for-1990 research decisions made for it went obsolete shortly after with the rise of cheap, powerful PC hardware.
> The gratuitous incompatibility made it almost immediately a museum piece
And yet it made it what it was.
The entire point of plan9 was not to be "Unix System 8" or whatever, it was to go beyond that and shed off the half a century of accumulated kludge. But if it had done what you are suggesting, that's exactly what it would have been.
I don't think this was a failure of Plan9, they just never intended it to be the case. After all, there is no reason to support c++, etc., when many other systems already do that quite well. The goal of Plan9 was to create new systems that would take computers in a different direction, and to do this it is better to avoid legacy.
> What this meant was first, you couldn't run stuff like a web browser on Plan 9 (and you still can't; please no-one write to inform me that some dweebish half-assed attempt at a web browser is a solution)
is needlessly provocative, given that these days it is impossible to write a web browser from scratch (https://drewdevault.com/2020/03/18/Reckless-limitless-scope....).
Granted, at the time it was possible, however that didn't fit into it's philosophy.
Notably, there was a way to interface to the internet -- Plan9 has a filesystem for exactly that purpose, all that needed to be written was the frontend.