> Unless memory mapped by the OS with no impact on runtime for unused parts?

Yeah, this is presumably why a no-op `uv` invocation on my system takes ~50 ms the first time and ~10 ms each other time.

> Exactly, so again have no impact?

Only if your invocation of pip manages to avoid an Internet request. Note: pip will make an Internet request if you try to install a package by symbolic name even if it already has the version it wants in cache, because its cache is an HTTP cache rather than a proper download cache.

But even then, there will be hundreds of imports mainly related to Rich and its dependencies.

rtld does a lot of work even in “static” binaries to rewrite relocations even in “unused parts” of any PIE (which should be all of them today) and most binaries need full dyld anyway.