I like the modern social contract and hotels, but to be fair, AirBNB is inverting what had already been inverted. In some sense, AirBNB is returning to the old model before hotels were everywhere. A traveler would reach a new town and ask for lodging in someone's home. In many countries, providing lodging to strangers is still the norm.
Yes, inverting it back to before there was regulations and a massive tourism industry.
The only travelers at that time arriving by the thousands would be armies, it's not comparable when scale matters.
Em. Tourism has been a thing, complete with travel guides, tour operators, souvenirs made for tourists and tourist attractions for millennia.
Plenty of major destinations (holy places, resorts, etc) would bring in thousands of tourists at a time. The ancient Olympics, for instance, brought in tens of thousands of visitors.