> "containers" broadly, including things like pipx, venv, or uv.

This statement makes no sense. First off, those are three separate tools, which do entirely different things.

The sort of "container" you seem to have in mind is a virtual environment. The standard library `venv` module provides the base-line support to create them. But there is really hardly anything to them. The required components are literally a symlink to Python, a brief folder hierarchy, and a five-or-so-line config file. Pipx and uv are (among other things) managers for these environments (which manage them for different use cases; pipx is essentially an end-user tool).

Virtual environments are nowhere near a proper "container" in terms of either complexity or overhead. There are people out there effectively simulating a whole new OS installation (and more) just to run some code (granted this is often important for security reasons, since some of the code running might not be fully trusted). A virtual environment is... just a place to install dependencies (and they do after all have to go somewhere), and a scheme for selecting which of the dependencies on local storage should be visible to the current process (and for allowing the process to find them).