Exactly this. I've had as many "serendipitous hallway conversations" in the last year as I had in the years before - just this time, they happened on IM, on videocalls, and in code review comments.
A small group of co-workers willing to sometimes go off a tangent in a conversation is all it takes. Doesn't have to be face to face, much less in a hallway or in front of a water cooler.
My feeling is the same: while random interactions are important, they aren't exclusive to an office setting. Weird logic. It's been surprising to me how much ink has been spilled about this, and how few solutions have been offered.