I'm sure you'll see lots of examples in answers to your question. You can add millions of not-household-name business programs to the list. Any OS that has bee

I'm sure you'll see lots of examples in answers to your question. You can add millions of not-household-name business programs to the list. Any OS that has been around a while, and is still active (aka Windows, Linux, MacOS etc) will have lots and lots of long-life software. It's an interesting dynamic because newer programmers have this impression that "software has a short life-span before it's eclipsed by something new and shiny." In truth, it's the opposite. Y2K showed us that software literally written in the 60s was still in play (30+ years) and stuff from the 80s (10-20) years was common. Even today COBOL programs exist, and that was unfashionable 30 years ago. Sure your web-frontend, JavaScript framework-based interface might not last long, but the real software doing the work lasts a long long time. This idea that you just rewrite everything every 5 years is a complete myth and yet every generation (including my own) has this impression when they start out. 20 years is actually not that old. When I attend conference's and take a straw-poll, many programmers there have a single product that originated in the DOS era, and have been actively built on for more than 30 years. DOS, 16 bit Windows, then 32 bit, even 64 bit, Web, Mobile, the more it changes the more it stays the same.