Anyone has ideas on how many successful tech companies are started by PhDs vs MSs vs BSs?
If you think a PhD will give you the skills you need to run a successful startup in the most efficient way, then you should probably do that, but I don't think the PhD distinction is going to do much for the first intention of "run[ning] a startup".
However, some of the big players do put a lot of clout into that kind of thing. All of the anecdotes I've heard indicate that Google, Amazon, Facebook, and others weigh formal qualifications heavily in the case of an anonymous resume. Many of Google's job listings state a preference for an MS or higher.
I think at high profile companies like that, where thousands of unsolicited resumes are received every day, strict formal educational requirements is a necessary way to pare down resumes queued for review.
At lesser-known companies, the qualifications are generally much looser, mostly focused on a demonstrable background with applicable technologies. You don't need any formal education at all for most jobs in the industry, just demonstrable experience and positive reviews for your past work.