Daniel Lemire:

Tenure is overrated. Most folks in industry that have worked just as hard as tenured professors, have savings, reputation and skills that are in demand. But if you are risk averse, then a government job is also quite safe even if you don’t formally have tenure. And academics with tenure lose their jobs all the time. There is always a clause saying that under “financial hardship” management can dismiss professors. And even with tenure, you still have to justify your job, constantly. If you create trouble, people can make your life hell. If you fail, people can humiliate you publicly. If you get into a fight with a tenured colleague, the fight can last decades and be unpleasant.

It is a lot easier to move back and forth between these occupations that people make it out to be. So while you can’t go back in time per se, professors move to industry all the time, and vice versa. To a point, you can even do both. It is not difficult to get some kind of honorary position with a research institute when you work in industry.