I think AirBnB was trying to have that vibe at the beginning. The problem is that you end up in a situation where that vibe doesn't scale. If you're trying to create a business worth billions, you need a lot more hosts and transactions than amateurs accommodate. An amateur might host someone for a few nights a month or a few nights per quarter. A professional is going to have an investment property that they're looking to book as much as possible and with the conveniences that make sure they get good ratings from guests.

I think a bunch of things have started out this way. Uber/Lyft: just people driving in their spare time to help people out and make a little spare cash. The problem is that if you're an app that just relies on people helping others out for a little spare cash, you don't have a lot of capacity. If you don't have a lot of capacity, you're just a cute niche thing that isn't worth much. So you end up relying on full-time drivers and you need to cater to them and figure out ways to attract and retain them. An pro driving 60 hours a week is worth a lot more than an amateur driving 4 hours a week every other week - 30x more. Likewise, a pro renting out an investment property 25 days a month is worth a lot more than someone renting a room in their house a few days a month.

I think you end up with a pivot from "oh, this is a cute thing with a little compensation" to something that's just a regular business.