(with apologies to Brian)
Those who can, do; those who can't, teach.*
- George Bernard Shaw
Those who can't teach, teach the teachers!- Laurence J. Peter
Those who can, do; those who can't, attend conferences!- Me
... I've no real regrets, Neil. If some poor person somewhere gets some benefit out of a bit of kit that I've fixed, that's probably reward enough. Similarly if someone gets some use out of something I've written (in computer code) that would otherwise have been out of reach (due to cost), then that's OK too. But yes, some financial reward would also be nice.

*
What this really means, of course, is that failures from other fields often find refuge in the school (or university etc.) environment. What's that lovely word ... tenure? Yes ... but there's an even sweeter phrase ... it's called "research grant"!