> That then leads to a precarious "all eggs in one basket" situation that leaves you vulnerable in cases of professional failure ("My start-up is not doing well; I am a failure") or burnout ("I'm cynical about my work; nothing matters").

I have such an annoyingly hard time with this. From a simple "couldn't achieve a technical goal I set for myself for the day" on a Friday afternoon ruining my Friday night and, through ripple effects, subsequently the rest of the weekend to I'm unfulfilled in my job therefore I'm worthless.