There is also a reason people lock themselves in their rooms to play games and watch TV shows, or schedule those activities around the time everyone else in the family is either not present or asleep. People like both social and individual activities, and I don't understand how VR serving primarily the latter is to be considered a problem.

You misunderstand I mean people meet up in real life (IRL) to take part in shared VR experiences where the other people are in the same physical space as you (and in the same VR space) exactly like getting together to play basketball or soccer. Think more of a holodeck kind of thing.