Orbital space tourism and space manufacturing could potentially make a significant market in terms of launch mass (that is, if you launch 1000-ton facilities instead of 1-ton satellites without necessarily occupying a large number of new orbits). But this is kinda speculative at the moment.

I think the real motivation for Starlink is precisely this -- there is otherwise no near-term market for greatly increased launch capacity. Starlink actually doesn't make too much sense from a purely technical perspective: in wireless point-to-point communications, distance is your enemy squared, both in terms of signal power and density. And it only gets worse when you have to punch through a cloud layer. But it is also the only near-term application that could absorb the launch volume offered by the Starship, so the two kind of feed off each other. This is not unlike the past ISS - Space Shuttle relationship, but at least the public is not paying for it this time.