I'm taking issue with the fact that you call a man who has a 1st career of 30 years "failed." (See above quote.) I say that a person with a 30-year 1st career must have had some degree of success, or the career wouldn't have lasted 30 years. I'm also saying that you have no basis whatsoever for calling the guy a failure. ¿Comprende?
Good point. I see what you mean, because if they were that bad, they would not have lasted 30 years.
But consider this, for what it is worth:
All of my very best Science teachers left teaching to go into industry or R&D.
None of my best engineering peers left to become teachers. The ones that did leave, should have.
At least this is what I have seen over the years. Does it really make sense to leave a successful career? Not to me. I would think that a successful career is too enjoyable to leave.
(Of course, considering the state of my 401(k) I may well be resigning myself to never retiring, and giving myself a pep talk!....)