Many answers ensue. "Lean is not a religion I'll say. It is not a panacea. It is about shifting the odds in your favor. If you are the next Steve Jobs, good luck! (sincerely, not condescendingly). You don't need #lean."
But there is another phenomenon among incredibly successful companies like Twitter, Facebook, Franklin BBQ (just back from SXSW, but no - I didn't - the line was 5 hours), Craigslist, and more.
Do you know the answer?
They were not TRYING to start a scaleable startup. They were just trying to build something cool, or something small but good, or something just for themselves or their own friends.
THE REASON THEY ALL SCALED is because they tapped into extraordinary existing demand by highly segmented customers with an incredibly simple and small solution at first.
So yes, they were all following what is now taught as #leanstartup (even if the brisket was Fatty)