Having kids does not exclude you from having a social life. Even one night a week to go to a local meetup would be great for improving one's network.

That was not included as a constraint.

That said, I do have a kid, and while he definitely represents a huge draw on my time and attention, I still manage to make and maintain technical connections outside of work.

Depending on circumstances, "we have kids of a similar age and both work in tech" is an easy instant connection.