Like the parent, I haven't found that's true at all. Most people doing residential work on houses work either on their own or in very small teams. They spend their time working on houses, not networking with other tradespeople. They might have a few people they work with regularly, but it's not a deep network.

Much better is local whatsapp groups where people who've hired good people can make recommendations. Those are a trove of good information.

I have tried exactly this, and it does not work. Nobody who did direct work ever had recommendations for peer workers. They just don't care. Most subs work directly with generals and not each other that much.

The general contractors know which subs are (currently) good and bad, so their recs are good, but you have to be friendly with them for them to share (instead of taking the project on themselves).

Professionals trade favors for each other. Someone who has done good work for a peer won't necessarily do good work if hired by some rando.