Here is my best attempt to articulate why I believe all dependencies, including compiler toolchains, belong in version control.

https://www.forrestthewoods.com/blog/dependencies-belong-in-version-control/

Dependencies Belong in Version Control

Why dependencies should be checked into version control.

@forrestthewoods There’s probably an interesting build on this essay about standardization, autoconf, and versioned package dependencies as a continuum of this solution (all the way out to Docker as you note but also starting with Linux package managers many years ago).
Related, object lesson I ran into recently: https://bugzilla.mozilla.org/show_bug.cgi?id=1866602
1866602 - Attempting to update version control tools results in KeyError: 'remote_hidden'

UNCONFIRMED (nobody) in Developer Services - Mercurial: configwizard. Last updated 2023-11-24.

@mtothevizzah Python callstacks like that trigger my PTSD. Urghhh.
@forrestthewoods Yeah, pretty opaque. Nice to have a very responsive dev, though.