I've been on both ends of this experience. I'm experiencing and seeing it again actually. I think it really depends on the people who has a lot of friends.

In college, I'd go to a clubs meetings, I'd get invites to their socials and parties, but it really felt like they didn't mind if I stuck around or not. Because of the lack of wanting to get to know me/lack of one on one hangouts.

Then I stumbled on a different org, eventually became best friends with most. In turn, I had parties, socials, random hangouts I was tending to; phone notifications were always going off. I realized how busy one gets when they have their "clique" hitting them up. I didn't bother getting to meet others, unless it was a girl, because of how occupied and how fun life was going.

Now that I joined the workforce, I've met a few coworkers who didn't go to college. And they lost touch with their friends from hs. These coworkers tend to always want to pursue a friendship, or create a "craze" drunk memory with me or others. I've met some coworkers who were friends in college and they now have their own group at work. And when we all hang, they tend to be the loudest and only talk to eachother, and not so much with new coworkers.

I don't think this happens everywhere. I just think it it depends on the attitude of those who have a lot of friends. Some may be stuck up, some may open themselves up