The real social network is the one you create on your own, with people you wish to network with. And it has to be small by design, otherwise it doesn't work.

Now, it doesn't matter what you use to create such a network, be that email list, facebook group, whatsapp, or fill in the blank.

No company or platform have been able to "create" such a social network for you. The best they can do, is provide appropriate tools for you to create your network.

And as far as I can tell, email lists still serve that purpose, irrespective of the hype the platforms like Facebook, Slack etc may generate.