I feel that a community can def be heterogenous AF. I participate in exactly that type of (IRL) community, and it is worldwide.

It does require some common focus, and common agreement that the community is important.

I do believe that we have those, here. The "common focus" may not be immediately apparent, but I think everyone here shares a desire to be involved in technology; which can mean a few things, but I'll lay odds that we could find a definition that everyone could agree on.

It is possible. I guarantee it.