Why do you think it was ever a bad idea? From the Airbnb wikipedia page, it seems apparent that, right from the beginning, the plan was to tap into the market of people who liked the idea of playing a professional Host but did not have the capital or desire to run a full fledged hotel/BnB; some of the margin gained by these lower costs of operating could be passed on to guests, thereby attracting them to the service.

However, HOWEVER, there are/were some gigantic risks Airbnb was taking, I will agree with you on that -- the risk of people staying at random strangers' houses and the wide spectrum of horrifying experiences that can lead to. There's an excellent Bloomberg article that does a deep dive into Airbnb's somewhat-shady "Trust and Safety team"[1][2].

The point I'm trying to make is that although the idea came with certain inherent risks, skillful execution can mitigate those risks significantly. Similar risks were also attached to Uber's idea of random strangers offering rides to people, and those risks were somewhat mitigated as well.

[1] archive.md link: https://archive.md/nyBFY

[2] original article link: https://www.bloomberg.com/news/features/2021-06-15/airbnb-sp...