Some of them will never stop using Fortran, ever, until they die. My old boss was trained with Fortran, and made a moderately successful career in particle phys

Some of them will never stop using Fortran, ever, until they die. My old boss was trained with Fortran, and made a moderately successful career in particle physics never needing to learn new tools. The ideas he needed expressed were short, he was good at explaining them, and it was never too big an effort to turn them into something that could run in PAW, ROOT, Python, VHDL, whatever was needed. He did the thinking, and expressed it in the language he knew best. He had postdocs, graduate students, and sometimes undergrads to do the leg work. Would he have had a better career if he'd spent time learning new languages rather than thinking about solving physics problems? I doubt it; and he probably wouldn't have had as much fun.