Mostly I recoiled in horror at bash specifically, which in addition to bash version, also ends up invisibly depending on a whole bunch of external environment stuff that is also updating constantly. That's sortof bash's job, so it's still arguably the right tool to write that sort of interface, but it ends up incredibly fragile as a result. Porting a complex bash script to a different distro is a giant pain.
Even for somebody that did not aim to have python programs for 20y, python is definitely not a good example of a "pdf for programs"
I've lately been pretty deep into 3d printing, and basically all the software has Python...and breaks quite easily. Whether because of a new version of Pip with some new packaging rule, forced venvs...I really don't like dealing with Python software.
A container has that already done, including all supporting libraries.
Edit: then ship the bash script in a container with a bash binary ;)
Entropy sucks.
These are different problems from the distribution/bundling piece, they won't be solved the same way.