So much "this!". The hotel/booking is the most blatant example, because the bar for "good enough" wouldn't really be that far up.
The only moat they have is worldwide discoverability (a regional cooperative just won't reach people who visit once, cooperatives would have to start global, or at least be really, really good at federating) and that the threshold for critical mass in that market is winner takes all: at least when you are not looking for that one spot for a two-weeks getaway (you might even enjoy trawling multiple platforms) but going through serial booking for a road trip (doesn't even matter wether it's bulk ahead or on the go),
Depends on the vertical. I would not be real comfortable booking lodging on some random portal, especially if we're talking more of an AirBnB thing vs hotels.
Yeah, that's one of the moats some have but booking.com has not: you don't just pop up a hotel from nothing, and the hypothetical failure mode of complete fakes appearing out of thin air is not only solved by payment on site but also by the local hotel owner community having a financial interest in policing their turf.
Or not, could be a fun plot for some speculative fiction: on a cooperative post-booking.com platform, hotel owners in a remote valley discover that they can earn quite nicely by offering "rescue nights" to guest who fell for a series of fake listings they keep up, untraceably because the fakes lack a payment channel to follow. Add some Bates vibes to the one hotelier who refuses to take part in the scheme for multi-layered tension.
A cooperative booking organization would have strong incentive to keep their members in the straight & narrow. It is a cooperation problem and institutional enforcement is a proven recipe for ensuring that.
If there were/are lots of small portals for each region/group of hotels, how would you know which portal is the (a?) genuine portal?
People on the other end of genuine transactions want/need some kind of payment from the people booking (to prevent at a minimum people booking lots of rooms with no intention of staying), but that's an attractive target for scammers. Especially as people often book things a significant length of time in advance.
The only moat they have is worldwide discoverability (a regional cooperative just won't reach people who visit once, cooperatives would have to start global, or at least be really, really good at federating) and that the threshold for critical mass in that market is winner takes all: at least when you are not looking for that one spot for a two-weeks getaway (you might even enjoy trawling multiple platforms) but going through serial booking for a road trip (doesn't even matter wether it's bulk ahead or on the go),