> Interesting that you refer Plan 9, but fail to mention Inferno, which was the final vision from the same researchers.
For the lazy like me:
I quite frequently see people mention Plan 9, but seldom Inferno. Does anyone know why Plan 9 became more popular?
Lack of teaching would be one.
I bet not many professors bother to dive into it.
The documentation is still available, http://doc.cat-v.org/inferno/4th_edition/, and you can get it as open source and commercial variants, http://www.vitanuova.com/inferno/
So it is mostly a matter of actually caring to dive into it.
Not only one will discover how many of the Plan 9 design issues got worked on, some of the design ideas that went into Go will be more clear.
It is also revealing to dive into Oberon OS linage and then see how some of its design went into ACME on Plan 9, dynamic loading on Inferno or eventually Go's method call and unsafe package design.
Instead most get off at the Plan 9 train station.
While not perfect, with their own set of issues, macOS/iOS, Windows (with .NET/UWP) and Android are a couple of steps into that direction.
Interesting that you refer Plan 9, but fail to mention Inferno, which was the final vision from the same researchers.
Regarding UNIX, one thing that keeps being missed regarding NeXTSTEP and its derived OSes, and to go along your remark, it that for NeXT and Apple, UNIX wasn't never relevant.
The UNIX compatibility was just a means to bootstrap the OS and attack the UNIX workstation market, the Objective-C technology stack (now Swift as well) was/is where the real value of the OS was.
Anyone using macOS or nowadays WSL as UNIX replacement, is replicating the farmer's story from the talk.