Most people probably don’t want to check a dozen different sites (convenience) or don’t know which sites they can trust.
Maybe that is true right now, but in the future I doubt it. The last place I rented was on both AirBnB and VRBO, VRBO having a slightly lower price.
When I'm choosing a place for a vacation, again, I'm looking at the top brands I know of, including AirBnB. Since the major hotels all resemble my business hotels, I'm more or less stuck looking at AirBnB rentals, simply because it's a more casual brand that I know of. I assume the vast majority of casual travelers are just like me.
I've had very good experiences using AirBnB in smaller towns, even in otherwise poorer places in Asia and Europe. On the contrary, I've had shitty AirBnB experiences, mostly in large cities in developed markets.