We saw that solar power venture unveil their idea. With lower cost/kg, there might be quite a few flights just to deliver piles of hardware in various new orbits. And these might require refueling launches as part of that process. Some delivered all in one place, some in separate locations.
Yeah, there are some very speculative markets. Solar power from space, commercial space stations etc. The chances seem relatively low that those would develop into a big market and require a lot of Starship launches. I currently don't see a big space economy on the horizon. Space (LEO) tourism perhaps could be thing to some extent when Starship gets human rated for both launching and landing. Because a Starship could actually deliver larger quantities of people, unlike Dragon or Starliner capsules, but this is still many years away.