People used to frequent in person things like specialty retailers, arcades, hobby clubs, religious groups, etc. When you meet real life people in person based on shared interests, you make connections across socioeconomic groups.
I just don't see nearly as much of this in todays society as 20+ years ago.
People with kids sometimes experience this via all the activities they take their kids to, but even there a lot of kids activities have become economically stratified. Instead of playing in the local $50/year rec baseball league, there's tiers of travel teams to meet any budget.