But that interactivity is pretty hollow. I'm sure it cures the itch but it's not the same as having a friend.

How do you know that it's hollow?

Beyond that, the second half of my first paragraph was about how some of those people probably become more than just acquaintances.

I think you don't realize how hollow the initial interactions were with the people you consider friends now. You have to start somewhere. It's just when you are younger you do not have a baseline of what a really good friend is.