I worked for a company in the '80s that made the Sharp PC3000 handheld computer. After resisting for a while (because the company thought it would be too expensive) they gave (lent) the dev team a PC3000 each. I thought it ran far too slowly, so I rewrote the ROM interface one evening in my own time. This made all the apps run a lot faster. The marketing department estimated that this had made the company £100k in direct sales, and £100k in indirect sales. I got a "programmer of the year" award but no hard cash. I don't mind though, I am sure that most of us didn't become software engineers to become rich! Later on I joined an insurance company (yes, yawn) that were going to rewrite the cobbled-together COM/VB/ASP/etc. website. I managed to keep it going and refactor it (by myself for a while); all the permanent members of staff left after one of the offices was closed. The team that took it over also wanted to rewrite it, but they never got round to it. I think most of them have now left. The cobbled-together classic ASP website is still in use (I reckon it is over 15 years old now). I would imagine it still makes them £millions/week. Even I think it should be rewritten now though!
Jon CodeWrite