See my other comment but also npm is installed globally and global packages are available so there is no isolation. Compare to Python where a virtual env is complete with a separate copy of the Python interpreter, associated tools (pip, etc.), and only local packages are available. And best of all, you can call binaries inside the virtual env from outside it as normal executables and it just works. No need to mess with $PATH or set any other env variables, just call ./venv/bin/foobar and foobar will run in the context of that venv. Recreating this on a different machine is amazingly simple if you can use one of the already available Python binaries on that system, and trivial if not (compiling Python takes a few minutes and there are lots of tools that will make that process even simpler than the two commands you need to do it). People talk about Docker being the universal environment to run things but Python development doesn’t even need that 99% of the time. And the standard library is chock full of sane, performant modules that allow you to do everything you need, from asyncio to parsing arcane binary formats. My installed packages typically number in dozens, not thousands like JS, because the standard library provides so much already.

You must be lucky. Anything the relies on their floating ABI breaks on every update (C dependencies are very common for certain tasks)

Yeah it’s pretty much this. Something simple like scss/sass breaks a little too often but that’s the easy case. When it’s a Postgres driver it gets even more interesting.