I sometimes wonder about this, I have a friend who does most of the organizing for parties or whatever. My sense is that there are a few different kinds of people, among those are people who, if they didn't organize parties, there wouldn't really be much of a platform for hanging out for them and others like them, while others are completely isolated, don't organize and don't have any other third space, and others yet have many smaller interactions from many other parts of life that don't necessitate a larger meetup necessarily. If you're an "organizer" type, my guess is that the people you'd hope reciprocate fall into the latter camp; they're happy to show up and have a good time, but they probably have a bunch of other things to explore that for some reason they haven't felt you'd be into... or a bunch of other possible reasons. Asking them to host a party is asking them to fabricate a social setting from thin air, but maybe they just organically don't find that to be something they need to do.

For me, I'll host something for a small group if I get some inspiration, but on a week to week basis I'm often in extremely social third-spaces, supplemented by larger parties (probably bi-weekly). My effort is often best spent meeting people for deliberate, intimate, outdoor sports adventures or coffee hangouts, but the same person I know who tends to organize larger parties doesn't really feel like someone who'd be into these; they can't really hold a conversation 1 on 1 for very long, and they're not super curious or vulnerable or athletic in the way that's necessary to engage in those as much. He's a regimented, scheduled, impatient, person. They often need a sort of fabricated social vehicle (also likes to decorate and host), whereas I get nearly all of my socializing from incidentally being in social space.

I think it's fine to be either of course. It's ok that my organizer friend doesn't like heights, and so I won't invite him to climb mountains, he likes hosting parties, so I try to attend as many as I can.

Note that I don't mean the non-organizer (me) is just passively socializing, it's just that they have different catalysts built into the things they do that extend into socializing easily. I'm DMing 1 or 2 friends, multiple times a week, to do something we both enjoy or just chat while walking around the city. While parties and hosted things are neat, they're just not very good platforms for depth.

Just as well, I do try and be inviting to everyone who'd like to come out and do other things, in general it's important to reciprocate, but I'm not hosting a party just because someone else did.