Comment by mklim

And the Bay Area is roughly 6,900 square miles vs the 3,806,000 square miles of the US as a whole. Put another way, Silicon Valley is where you can find 10% of the total number of US developers despite it being only ~0.002% of the country's landmass. I get the general point the author is trying to make, but 10% in such a small region is still an extraordinarily high number.