It’s actually $120 for the highest deluxe edition, which includes the 787, SFO airport, and Heathrow. I imagine a decent chunk of folks on this site wouldn’t want to play without the decked out SFO experience.
My guess from the list of premium airports is that Microsoft has made a judgement based on wealthy geek density. People love to fly their local or familiar airports, and the kind of people in San Francisco who play flight simulator are wealthier than most. All the premium airports are either tech or financial hubs.