Honestly, that's kind of why the BFR idea kind of worries me. It feels like SpaceX analysed the need for orbital space-flights, and realized there was unlikely to ever be the kind demand that would provide the economies of scale needed to do what they want. On the otherhand, there's undeniably a large demand for terrestrial travel, so they came up with a way to use rockets for that purpose. It feels like something to show investors, rather than a workable plan.
But hopefully I'm wrong. Economics aside, its certainly cool, and it would be nice to have an application for terrestrial missiles other than nuclear annihilation.
"with so few flights" is the operative phrase there.
Current launch market is about 60-100/year.
This is why SpaceX invented its constellation: not only does it allow them to make a lot more money than just doing a few dozen launches per year, but it allows them to generate their own demand for launches to justify these crazy Mars rockets. The constellation is for about 12,000 satellites replaced every 4 years or so. Initially 500kg, but Mueller (rocket guy) recently hinted they could get much larger (so let's say 50-100 tons). Therefore, they'll be able to self-generate between 30 and 3000 annual BFR launches on their own. This point to point thing is another add-on market, could be even larger from a launch volume perspective (but, interestingly, smaller from a addressable-market revenue perspective than the constellation). With 3000 flights per year and margin to spare (and the benefit of post-inspection of the rocket in case of a near-miss), you should be about 100-1000x as reliable as today's crewed rockets just to start. Now add point-to-point, and you can do 50,000 BFR flights per year...