I realized a) that I was unlikely to get a tenure-track position, and b) that even if I were to get one, I didn't really enjoy the work of a tenure-track professor, which tends to be more about fundraising and having meetings, and less about doing research.
(More flippantly, I realized that the life of a modern, tenured academic looks a lot like the life of a small business owner. So why not just go into startups, where there's a chance of making real money for the lifetime of effort?)
