Why doesn't AirBNB just vertically integrate to make some of these issues go away? They could have AirBnB locks, which only open via the app after payment and approval for the guest is received.

For cleaning, they could hire out cleaning to the hosts or even the guests for a discount, or they could acquire someone like TaskRabbit or an Uber-for-cleaning type app.

To me, it seems they're taking the easy way out by not doing much about the issues and letting hosts deal with it.