It’s not nothing, but the difference is at least an order of magnitude.

Consider: I am probably 0% likely to book an Airbnb in my own city. Almost all of my Airbnb’s will be somewhere else, so I only really care about remote stock.

By contrast, something like 90%+ of my Uber rides are going to be local. In many of the places I might travel to, I don’t need Uber at all (the location is rural/suburban, the public transit system is cheap and effective, cabs are widely available, etc).

That is a good point. But presumably most of Uber's revenue comes from the residents of a city who are in town most of the time. Opening up in a new city doesn't benefit Uber as much as it does Airbnb where all properties are accessible options to all of its users.

But the New Yorker knows that AirBNB is the place to find their place in Tokyo, with few non-hotel alternatives. When you got to Tokyo, even if you don't have Uber installed, you will find a cab.