No, my original comment was about major providers shifting to non-public channels.
G+, or its G-Suite successors, still exists, but as closed networks. Similarly Yahoo Groups.
In looking at G+ Community size, open vs. closed participation was a huge factor in membership. Simply open vs. closed (mod approved) membership had a substantial impact:
Users and visits pose little loss risk. Revenues do.
https://www.feedough.com/reddit-make-money-reddit-business-m...
2019 Revenues: ~$100 million.
https://marketingland.com/reddit-us-ad-revenues-could-top-10...
FB 2018 revenues: $55 billion.