St. Thomas is part of the United States of America and Tortola is part of the United Kingdom. These are not poor countries. Otherwise, I agree with your point that taxis in St. Thomas and Tortola are plentiful. At Magen's Beach in St. Thomas, taxis are lined up in the parking lot waiting to take people back to the ships.
The people selling their goods and services on both islands appeared to be poor. It was a new experience for my kids.