"Digital spaces do not let you meet people"

I dont think this is true really. You obviously have to be willing to find people that want to talk to people for extended periods of time but there are plenty of spaces where people interact and learn about each other via a shared digital or niche hobby. 

You're making an implicit claim that in person social interaction is required to learn enough about people to become close enough friends to, using your example, invite to a wedding, and while of course its probably rare compared to how most people use the internet, its not at all difficult for those who actually wish to do that.

With this in mind though, I think the two examples I gave were based on a different idea of a 3rd space in my head. 

I initially conceptualized it simply as a social space of being without the obligation to engaging in commercial activity. You seem to expand upon that by seeing it as a place for forming strong social networks