> brokers need to be licenced real estate agents (even as a buyers agent in many states), so I suspect there's a relatively decent culture of people who are serious about selling their business going through brokers and resulting in listings on at least one of the major platforms.

Works like this in US too. Commercial brokers rely on their network and not listing things on a market. Even most commercial real estate property for sale in the US is unlisted. It’s a weird industry, there are listings site but they only reflect a minor percentage of what you’d find if you drive around looking at for sale signs.