The hyper-specialization we're talking about is specifically a way to avoid having a social group. While the hikikomori may not have exclusive interests, the whole point is to avoid physical contact with anyone at all. Maaaaybe I just can't see far enough into the future, but personally I think physical contact with other people is still pretty important.

Also partaking in popular culture doesn't mean pulling everyone alive that's interested in that culture into your social group.