How come AirBnB become widely successfull as compared to Couch Surfing yet Couch Surfing existed way before?
My take is: CS didn't directly lose because of AirBnb, because they appealed to different audiences. CS "failed" because of their own internal problems and inability to monetize without destroying the sharing-based culture. It also started turning into a dating service, which kind of killed the original traveler-focused vibe.
AirBnb succeeded because it tapped into the economic desire of people to make money from their spare bedrooms and apartments, which then grew into its own "profession." The immense amount of VC funding didn't hurt, either.
I also feel like the average person is more introverted and skeptical of strangers than circa 2005-2010, and this broader cultural trend impacted CS negatively while benefiting the transaction-based nature of AirBnb.
One says sleep on a stranger's smelly couch and impede on them in their home. Good for broke and social travellers perhaps.
The other says informal self-service hotel, with the freshness, easyness and carefreeness of air.
A lot goes in a name.