Social networks for humans are the exact opposite of at risk. They're among the services most likely to continue to be used by humans, even if we suffer mass unemployment. Facebook, Instagram, WhatsApp are free to use (if you're unemployed because AI shredded your job, you can keep your FB account regardless of your income) and have extreme operating margins.
The desire by humans to be social online isn't going anywhere. Rapidly advancing AI isn't going to make people stop wanting to connect with other people they know via social networking.