If Colin knew that he would have proved Birch-Swinnerton-Dyer as an academic, would he have regrets about leaving academia? This is clearly an academic (no pun

If Colin knew that he would have proved Birch-Swinnerton-Dyer as an academic, would he have regrets about leaving academia? This is clearly an academic (no pun intended) question, but I say it to illustrate a point: it's hard to know if you made the right choices in life, since you don't have perfect information about the course of alternative paths. I have been in academia and industry. I suffer from 'grass-is-greener' syndrome right now in industry, and am pining for more research. But I don't know if I would have felt the same way if I were stuck on a postdoc-to-postdoc treadmill.