I've entertained very similar ideas myself. It's one of those things I often revisit -- wondering if I had made the right career choice. I love being an engineer and have been very lucky in being financially rewarded for doing something that I love. But whenever a startup I'm at fails or I feel my career is at a standstill, the things that's given me joy during those times are the times I've spent helping others outside of my career. I think it's because acts of kindness and generosity are meaningful in and of themselves whereas a career in engineering might make sense in the end or maybe not.

A good friend of mine actually had a great career in software but decided that to become a nurse in the time he has left on earth. He and his wife both decided to go to nursing school and were definitely the oldest students. They are both now nurses and seem very happy.