I agree with a lot of your points, AirBnB has just made it much more accessible (they're not alone just the point)

Regarding living like the locals live, of course it's not exact. For example, knowing the language matter a lot, but it's a very different experience to staying in a Hotel in the middle of the old town. Many cities that get rave tourist reviews are not near as nice if you don't stay in the tourist quarter (for example).