Really depends on your team, in my experience. Nothing wrong at all with being a middle-aged parent who's too busy to do things with coworkers outside of work, of course. It's a workplace, and we're here to do work, not hang out. But my friendships at work tend to happen with people who are around my age and are interested in doing fun things together outside of work too.

Maybe it depends on your definition of "friend" as well. For me, no matter how well I get along with someone at work, so long as we're only chatting with each other over lunch and coffee breaks and the occasional team event, we're just acquaintances, not "real" friends in the sense that you hang out just for fun and help each other out with things that come up in personal life.