I think about this often, but then I go for a walk (or in other cities, a drive) and see packed bars and restaurants every night with people from all ages having a good time. Makes me feel like the problem is on me - people are obviously able to make friends and hang out without any special apps beyond what is available now.
The only new people I’ve met at bars are friends of friends, not random strangers. And when people are with their group of friends, it’s hard for a stranger to jump into that dynamic.
For recent transplants they roam bars until they find one with more singles and folks looking for social interaction. They do exist, but are probably more rare.
My theory of course is that the latter type of bar morphs over time (decade+) into the prior type of bar as "friend groups" get established at the new place. The new place slowly turns into the old hangout spot.