Many, many factors: 1) The average American lives 18 miles from his or her mother. Leaving one's hometown for a tech/finance/arts hub is for the upwardly mobil

Many, many factors: 1) The average American lives 18 miles from his or her mother. Leaving one's hometown for a tech/finance/arts hub is for the upwardly mobile elites, not the masses. HN's demographic is extremely unrepresentative. 2) Foreign language education is poor. K12 schools generally make a token effort towards Spanish, French, and German. Asian language education is rare. Bilingual children are generally from immigrant families, or from very wealthy families who can afford good schools, study abroad programs, a gap year or summer for their teenager to wander around Europe with friends instead of working, etc. 3) International travel is extremely expensive and most people do not have that kind of cash lying around to cover necessities, let alone leisure travel. Most Americans live paycheck to paycheck. So going abroad is just not a familiar or natural experience to many people. Only 46% have passports.