The other interesting comparison point is Sabre: completely the opposite end of the distribution scale and not a rapid growth company, but they're significantly more profitable than AirBnB at a tiny fraction of the valuation (and have an excellent moat)
There's a Booking.com ad in Australia that is very AirBnB-esque (to the point that my partner thought it was an AirBnB ad until the Booking.com tagline came up); so my feeling is that they're ready and keen to compete in that space.
Perhaps a cynical or unpopular point of view but until the technology becomes a hindrance, does that really matter? Its not as though people are going to these sites because they have great technology. They go to them because the prices are good and they have good UX I assume?
It is very cell phone and cable billing, there is only a very loose relationship between the advertised price and what you will actually pay.
I think HomeAway was a little bit better about this, amortizing the fees over the length of the stay and including in the listed per night price.
I used to run infrastructure for Booking until a couple of years ago. I'll honestly admit that there's lots of tech debt. AMA - but I'll say that I'll provide no response time SLO due to work travel.