Why would you want to have a random conversation with someone unless you had common ground/shared interests in the first place? Are you just looking to meet anyone, or people will have a genuine connection with?

I agree that it's hard to meet close friends as an adult and it's hard to find "the one" romantically-- but that is because, the older we get, the more points of commonality we expect to find in our friends/partners. Just going to the same high school or college isn't enough to become friends and just working at the same place isn't enough to find a life partner. Plus, all of the reasons why we grew apart from an old friend or broke up with a previous partner tell us the things we AREN'T looking for-- because they were deal breakers before. So, with each new relationship, we try to find someone even more compatible. That can be hard. But it isn't impossible. It's about finding those people who share our interests, beliefs, hobbies, etc.

Personally, I have zero interest in shallow conversations or just "stopping to talk" with strangers. I avoid it at all costs because it wastes my time and slows me down when I'm already busy and short on free time. I am, however, still interested in meeting new people with whom I might have a real connection. In order for me to want to get to know someone, however, we have to have some basics in common: progressive politics, education, emotional openness/depth, a shared hobby, etc. Without that baseline, I don't really see the point. I'm never going to have deep conversations with someone who has a completely different worldview. Why would I prefer that person's company over the friends I already have, who share my worldview? I don't want to spend my free time arguing or debating. I want real human connection with someone who I don't have to "work" to spend time with.

The way I have met new people is through online dating sites (both partners and friends), meetup groups, volunteer work, political organizations, social groups centered around my identity, etc. Sometimes it's a hit and sometimes it's a miss. But, after a few misses, you will eventually get a hit.