I never took the job at Stack Exchange for the money. In fact, I had a small pay cut. I took the job because I was in love with the mission, I knew I could change things and make the Internet a better place. I think I did in my own little way. I love the fact that I am leaving this job with a big pile of public artefacts. This is worth much more than cold cash.
However, I am not getting any younger, I would like to have a large stake in the next project I take. The only way to have a large stake is to be a founder.