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.
My only worry is if one day they decide to stop supporting it (even if it's 10 years in the future) and all of a sudden it's not possible to fly around because the service that streamed map data from the cloud isn't running.
Hopefully modders would reverse engineer the executables to talk to their own servers (presumably it's not as simple as modifying a DNS server to return a homebrew IP address, and there are baked-in SSL certificates) and get the maps that way...
Hah, imagine doing that and streaming a map of Mars. Or the heights and structures from a Minecraft map. Or a Sim City map, Sim Copter 2020 anyone?
Afaik, there's an offline mode. It seems like you're forced to complete an online update before you're allowed to start the game proper though and you might be stuck with the original data on the discs even if you could skip that, which would sort of suck.
The game client is about a 91 gigabyte download which will include all the aircraft and a low-resolution copy of the entire world. This offline data is fully functional.
You only need to be online for multiplayer, live air traffic data, and to stream high-quality versions of the world.
Also, the game has an option to manually add areas of the world to the high quality data cache, so if you know you're going to be without Internet for a while, but still want to be able to fly over certain areas with high-quality imagery, you can do that.