Since they tend to be in management or company ownership they keep on earning and getting richer but their money doesn't go out into the economy. This also applies to their relatives who tend to be high spenders.
They are still spending money though in different ways - less fuel, fewer air tickets and hotels, but more take-out, online shopping, subscriptions and so on.
You don't have to be rich to go to Stanford.
... or brilliant to get a CS degree! (EE major here)
uses the energy contained in that 5 miles of height they still have
You're thinking about the RAT (Ram Air Turbine) that works like a windmill to generate emergency power to operate certain basic electrical and hydraulic systems in order to make a controlled descent possible. The APU (Auxilliary Power Unit) is a small jet turbine (usually inside the tailcone) that is used to power the aircraft on the ground before the main engines are started. The APU burns fuel just like the main engines (just less of it) and provides electrical power rather than thrust.
Everything that can be invented has been invented. -- Charles Duell, Director of U.S. Patent Office, 1899