As a parent I foresaw that I would make acquaintances with others who go to the park, or live on the street. So far we exchange polite pleasantries but there's just nothing beyond that. It should be unsurprising, the prospect of any change in routine is more uncomfortable and daunting when you're a busy parent, and friendship invites more overhead. There are friends I made after moving to a city that I barely want to see now, mostly because there wasn't enough in common in the first place.

Strategy wise if you're unattached and have free time, making commutes to events and planned activities is still a more effective way to make friends.