None of those places are meant as hangout locations, and all of them require paying. Malls were useful to kids because being there was free for essentially an unlimited amount of time. Sure, you'd buy a soda once in a while, but that's not enough to be allowed to spend 4 hours in a bar or restaurant.
A closer use case would be neighborhood centers, but in my area, those are mostly closed in the evenings or at least reserved for private use.
Where do you live that you have to pay to access a public park?
Kayaking (not whitewater) and fishing are my two favorites especially if you combine the two. I usually talk to any fisherman I see and people come up to me at the ramp to chat.