I would imagine that a 14% price increase to the end user will absolutely move the needle. That's massive.

You don't collect revenue * tax when you introduce a tax. The artificially increased price pushes down the demand and will likely force suppliers off the market, lowering revenue overall.

I could draw the supply and demand curve, but it's pretty straightforward.

I would guess they won't see anywhere close to $11M. People will simply start listing on Craiglist or other forums and avoid the whole AirBnB hassle.