That's a question about demand. My goal is to move all resource extraction and heavy industry off-Earth, and to open the space frontier to permanent and self-sufficient human settlements. For that many, many Starships will be required.

Note that the killer feature of Starship, IMHO, is in-space refueling. This isn't a Earth-based heavy-life vehicle... it's a re-configurable spaceship able to explore the entire solar system through fuel depot staging (with Starships themselves serving as both tankers and fuel stations).

I think launch demands might expand to fit the capacity. It’s hard to predict what uses people will put a new technology to.

“I think there is a world market for maybe five computers.” -- Thomas Watson, chairman of IBM, 1943.

Plan is to get a million people to Mars within a few decades. You can only fly every other year when orbits sync up. Initially, I imagine many Starships will stay on Mars as shelter and raw material.

Then there is the idea of using Starships for very fast transport on earth. Fly from NYC to Sydney in half an hour. If that catches on, they may be replacing part of the airplane fleet.

Then there is lunar shuttle services, satellite transports and asteroid mining.

My guess is: a lot.

It's not just re-usability, but turn around time as well.