Seems Like Finding Real Friendship Is Frustratingly Difficult At Meetup Events

Is it just me, or do other people find it difficult to establish real friendships at Meetup group events?
   You attend an event. Perhaps a hike, dinner, whatever that a Meetup group puts on. You’re friendly and upbeat. Have a few good conversations with people.
   Seems to go pretty well.
   But when you try to start a real friendship outside the event by sending them a follow up message afterwards, it becomes clear nothing is going to happen. They don’t respond or say something like “nice to meet you too, maybe we’ll run into each other again at another event sometime.”
   Hmmm…
   For me, I am lacking in terms of friends, but I suspect most people attending Meetup events already have close friends, dating lives, and possibly significant others too. As such, they aren’t really looking for a new friend, or don’t need one. For them, it may be more that they don’t want to do things like that alone. Perhaps the people in their lives weren’t interested or available to do that activity.
   Whereas someone like me does things alone all the time. I’m attending a Meetup event trying to find a real friend, but most already have that.
   Coming at it from different perspectives.
   At least, that’s a theory of what could be a factor.