Postal mail is also available to everyone, but it's as functionally equivalent to Instagram as RCS is.

"I want Instagram" and "I want to be in touch with my friends and family" are completely separate things. You don't need social networks for that. It was possible to be in touch before the internet and I believe that Instagram didn't improve it at all.

By that logic, we could simply ban the internet and save a lot of trouble. Society functioned without it for thousands of years.

Why go to extremes? The internet does improve the friends&family communication a lot and is useful. I'm saying that Instagram and other social media don't improve it that much beyond direct communication.