You need shared contexts and shared interests. The reason why it’s difficult to make friends as an adult is because where there's shared context (seeing the same people over many months daily i.e. workplaces), there's a lack of shared interests. Where there's shared interest (hobby groups, bookclubs, etc), there's a lack of shared context. A place
The ersatz third place is a consequence of a culture obsessed with productivity and status, whose subjects might have decent incomes but little recreational time.