What is your opinion of people who switch careers and return to school later in life?

My dad knows a guy who got a PhD in chemistry and he worked decades in his field and then returned to get an MBA and now heads an investment firm with thousands of employees underneath him. I watched a YouTube video where a female Wall Street banker left her career to get a PhD in psychology and work as a psychologist because she wanted a job that was more personal than just number calculations all day long. I had a professor who had a degree in actuarial science and he did not enjoy his job so went to redo a second degree in humanities and then went to Harvard and got a PhD became a professor

What is your opinion of people who switch careers and return to school later in life?
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