You're not wrong, but it seems to me the "addiction problem" of social media is not so much about the interactivity, but has more to do with the near infinite supply of entertainment.
I was about to say much the same. I deleted my Twitter accounts years ago now, but I still find myself reading the tweets of Charlie Stross, amongst others, multiple times per day.
it's a complicated issue and you're right that the the unending source of dopamine hits from entertainment would certainly play a role - although that's not really unique to social media. I personally think that a bigger factor may be the instant gratification and validation that comes from followers/likes/comments/whatever. I think young kids especially (but certainly not exclusively) crave validation from their peers and social media is a perfect place to turn to for that.
I have no mouth, yet I must stream.