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).