But it's not even just that. Even within a major version it changes so much every few months and between different distros and platforms that random non-packaged scripts never work when moved from the authors fedora box to someone else's debian box, or god forbid bsd or sco or windows, or the same box a year later due to any number of random library/module differences.
It's great for the author and miserable for every other user.
It's ok for writing and using today and not at all for writing to keep.
It's ok for packaged apps where the package manager ensures that the script has exactly the environment it expects.
It's ok for controlled environments where the gods at the top have decreed that it is just part of the environment, so, large companies with IT departments and static published environments that everyone must use the same.
That's a lot of "it's ok"'s and so that's why it exists and is used in many places, but none of those changes why it's quite terrible.