but I am wondering, are there many people out there who found their years of a PhD helped them much on their start-up?
sorry for the snarky comment, but i'm pretty sure 10000% of HNers will agree that a Ph.D. is definitely an anti-prereq for doing a start-up; in fact, it's probably the worst use of your time if your goal is to found a start-up (UNLESS you want to develop your Ph.D. thesis into a start-up, which is hard, since what is popular in research and what makes $$$ are largely uncorrelated).
that's like spending 3 years earning a law degree and then complaining that it didn't help you with your goal of becoming an Olympic swimmer
From the experiences of people I know, it helps if your startup is either capital-intensive (think building a chip) or is solving a really hard technical problem (think Google, DNA sequencing, or auto-parallelizing compilers). In those cases, the fact that you ostensibly advanced human knowledge in some small way serves as a predictor that you might be able to do it again, which inspires confidence. If your startup doesn't fall into either category -- and most don't -- it's less helpful.
I think what I find annoying/confusing is that on HN articles that have to do with PhDs are voted up and people are generally pretty positive about PhDs, rather than emphasizing that they are a waste of time to people interested in start-ups.
HN doesn't seem like the appropriate place for PhD info.
HN is no longer just Startup News, as it used to be. Topics which are of intellectual merit appeal both to startup founders as well as to PhD students. Hence the large number of PhD HNers and generally rosy picture of PhDs.
But I agree with the grandparent that getting a PhD is somewhat opposed to doing a startup (although you need many of the same skills for both).