I know a couple - just had lunch with one of them a couple days ago. One does contracting + part time teaching at a college. Another just cashed out of a startup with enough money to never work again (after having previously gone public with a startup with enough money to never work again, but kept it in the company's stock, which tanked along with the company).

Both of them have held managerial positions up to VP-Eng, yet decided it was not what they wanted to do and downgraded themselves to rank & file software engineers, albeit very good ones.