Facebook has been in a traffic nosedive for years now and forums are coming back, except this time registering has to be 2 clicks and very simple. No capcha's, no checking e-mails for links, no waiting for mod approvals etc. A lot are using discord but thats not the silver bullet either.

A facebook car group is no different than having a car show at the entrance to a walmart, because its the same people showing up, offering "advice" and asking questions.