Rich people have boats, by definition these are people with too much money to spend and is a huge market. Airplanes? This will revolutionize coverage on long haul non-polar flights.

Trains? Buses? These both have density issues with the existing cellular network. How many times have you come to a halt in a traffic jam only to have horrible cellular coverage due to the local cell site being overwhelmed?

5G doesn't solve any of these use-cases. There is plenty of room for adoption of starlink at premium prices.