It's really not OK to say, "tl;dr - dull, pointless". That's the critique of a particularly young child. If you want to critique - fine, go ahead. Explain why corporate life can be fulfilling. Explain why the stable career is good; point out philosophical flaws in the argument for going off and doing a start-up based on personal angst. I'm quite sure that to the thoughtful critic, there are quite a few more ways to break down and point out issues.

But it's really not a story about "why I left X to start Y". Sure, that's the narrative. But the point of the story - that so timeworn story so fresh for each person who takes that journey - it's about "why Z at all".