Also, referrals still have to go through interviews, so it's not really unusual to interview someone who is senior and skilled.

Right, and that's why we still source and recruit, to pull in people from outside of our community. It just has a much lower hit rate.

That’s not true. You can have people who are in multiple communities refer in someone from outside.

I’ve had it happen to me and done it for others.

Its the old boys club. You do realize there are tons of programmers in just the US that have no contacts with the coasts? This is what makes the Ivy League so valuable which is very good at discriminating over large groups of people.

My favorite is businesses and colleges that don't take applicants from PO Boxes.