I have perl code I wrote in 1992 that still works properly, without changes. The binary executables have changed ISA from MIPS 4 to x86_64, and are compiled fortran (gfortran). There's even a switch I use to be able to read the large endian binary files in gfortran.
My c code from 1996 requires rework. My C++ code from 2014 requires rework (I had to do this with others code as well to use a std capability). Python code rarely survives 3.6 -> 3.12 never mind 2.7 to 3.x. I worked at a company that had (very unwisely) written a massive part of its infrastructure in Py2.7, and was using it a decade past its expiration date.
I, too, have 20 year old perl scripts that still run fine.
I randomly have to bang my head on my desk over bs with python and php incompatibilities between versions.
Pets perl