(author here) Thanks for the comment! I do think you hit on something interesting, and it partly explains why the project is so big :)
To me, shell and Python/JS feel kind of similar, and that was sort of the thesis at the start of the project.
But if you just incrementally add features to Bourne shell, you basically get Korn shell, which is where bash got all the "bashisms" that people don't like.
This paper was surprising to me; the proprietary AT&T ksh was used for GUIs and so forth, AND it was embeddable like Lua:
http://www.oilshell.org/archive/ksh-usenix.pdf
[ksh] has the capabilities of perl and tcl, yet it is backward compatible with the Bourne shell. Applications of up to 25,000 lines have been written in ksh and are in production use.
Much of the impetus for ksh–93 was
wksh, which allows graphical user interfaces to be written in ksh.
It's a lot more work to make something like Python or JS! Garbage collection is one issue; shells don't have it because they don't have recursive compound data structures or true functions.
So I would say that ksh "failed" because it took a lot of shortcuts. Perl, Python, Ruby, JS, and PHP won. So with Oil I also am upgrading shell, but it was a lot more work since I wanted to make it like the latter languages. It wasn't obvious at the outset how different these things are!
So in a sense Oil is upgrading shell to be more like the languages that won, which I still think is a good idea. It's weird that every computer boots to into a programming language REPL, but you're discouraged from learning it because it sucks. There's no reason that language shouldn't be a good one.
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Yes pipelines are a big deal and the runtime is solid now so they can be enhanced. Ideas here, feel free to chime in: https://github.com/oilshell/oil/issues/843 :)