Saying everything above as someone who's switched advisors (and field of study) five years into their PhD program, and finished it.

I strongly feel that the "myth of second chance" rhetoric is just sunk cost fallacy by another name.

Especially given the conspicuous lack of concrete examples in that rant.

----

PS: You sounds skeptical of what I say. May I ask your age? Defeatism seems to be a feature of the younger generation these days.