So having worked way too hard on my startup only to have it fail, I can somewhat relate to this (I do not pretend to be as amazing as Greg). You're right - after my startup failed people were throwing what were objectively great job offers at me. Even more amazing, many of my investors were encouraging me to start another company and were willing to give me fantastic terms just for agreeing to start a company (entirely at the idea stage I could raise 7 digits at an 8 digit valuation with no strings attached from investors I already knew to be great people).
This ignores the mental toll that exhausting yourself on a company takes though. There are lots of people that start companies, but many people quit when the going gets tough. Those that commit everything to it are praised when they succeed but mostly forgotten when they don't. I am just now recovering after several months of not working, catching up on years of lost sleep, and basically becoming a person again.
There are days when I regret it and there are days when I don't. I learned a hell of a lot and I recognize it has opened doors for me, but the real question is was it worth it? And that's going to be different for everybody.
An important note, which is particularly relevant for HN. Paul Graham once said Sam Altman was the right person working on the wrong problem (with regards to his company Loopt). I bet there are a lot of people like that who just commit themselves to the wrong thing.