Yeah. I can easily run FORTRAN code from my PhD supervisor's PhD supervisor, written way back in the 1980s, but I cannot run some of the Python scripts written by a post-doc 10 years ago. It's a mess of abandoned libraries and things that work only with some specific versions of some libraries, and compiled modules that rely on the dodgy behaviour of an old compiler. Perl seems to be better, if only because people used to rely much less on external libraries.

But properly running code is not the solution either. I can count on the fingers of one had the downloads of some of the codes we've published (easily compilable modern Fortran), and AFAIK nobody ever published anything using them. Having a multitude of codes available does not mean much if nobody runs them, assuming they can be compiled. And I would guarantee that none of the scientists who download these codes would be able to understand what they do in any detail.