How are some people able to have such large social circles and so many friends to go out with?

I have gone out to bars and nightclubs a great deal in recent years and it seems like some people are regulars at these places, able to head out in large groups of friends.

In high school and college, I understood it because you could pay for friends through Greek Life or just by being one of the cool kids with rich parents.

The weirder part about this is that I have dating figured out and can get a date a week from dating apps alone, meeting women has been easy for me. A mystery puzzle for me in social life has been social life outside of dating, how some people are able to get to that point where they have a lot of friends or at least a lot of acquaintances.

How they seem to be socially connected to so many different people and are always going out to clubs with a large group.

Is it mainly done through old friends you made in high school and college once you are past your early 20s? Since so many people settle down after the age of 22 or at least become very closed off to making new friends to party with after that age.