This feels like a plea for Fortran that has hindered some of the other communities of scientific software like High Energy Physics where they are struggling to

This feels like a plea for Fortran that has hindered some of the other communities of scientific software like High Energy Physics where they are struggling to get key software ported to C++. If the SciPy community glues itself to Python 2 it's just going to be that much worse when Python 4 exists years from now. I agree with a lot of the other people commenting here that you should be able to reproduce the results with the code at the time it was written, if that is not being preserved as either an artifact or a versioning piece that is a process problem when releasing work. Losing the work generated before or making it not clearly reproducible is bad, but trying to be a stick in the mud will prevent advancement for the generations hereafter as well as for the High Energy Physics example: when was the last time you see undergraduates taking fortran en masse? Keeping an esoteric version of software only helps you unless you make sure it helps those who come after.