If they desire a harsh rigorous review mechanism it doesn't seem very hard or expensive to build. Anon reviewers, top noch reviewers, they can have many tiers.
It isn't the journal that has prestige but the track record of its reviewers.
Mirror the topics on a discussion platform with separate sections for different skill levels. Heavy contributors earn bragging rights.
Mirror the topics on a wiki and have experts approve edits. There is prestige in just approving contributions and having conversations.
A chat client is also imaginable where one approves/adds contacts by type of publication.
Each can run rare expensive advertising that lives up to unreasonable demands.
But no? That would hurt the reputation - just because?