Ironic is you making that statement with over 1400 posts.
But you don't really know why people choose to be here. Some may have crippling social anxiety and if it weren't for the internet they may barely talk to anyone at all.
Others, no doubt, have physical disabilities that make it hard to get out and meet people.
Nor do you know how much people interact offline. It may be plenty.
Also different people have different needs. I, for one, don't care for a lot of social interaction. Being online allows me get much of what I need, that would otherwise be uncomfortable to me. And when I get close enough to some people I will talk to them in other ways.
Also forum chatting is a much different creature and allows for more thought to be put into everything someone says. This allows for richer, more thoughtful discussions.
Interacting with people no longer needs to be limited to one thing. Communication is not one size fits all.
This thing you criticize for lacking intimacy may be someone else's lifeline.