Swede here, I used to host a lot of dinners and parties.
But then i realized that it was mostly me who hosted them and the few times i got invited there was an agreement that guest chip in on the costs or that it was a potluck kind of thing.
Made me regret spending all that time and money on the parties i hosted.
Sounds unfortunate but I don't think there's anything to regret, you spent time and money no one else was spending but you still (hopefully) created positive experiences in return.
Freeloaders. It tells you something about the relationships that those "friends" choose to build.
If the only friends you have are those you have to pay, when the money's gone, are they likely to stick around? (Likely not)
But if they do, then maybe you've found a true friendship.
i really started to loathe potlucks. i'd rather not be invited tbh.
What do you regret exactly? I have found that friendships are rarely balanced in that sense. Sometimes you spend more (effort, worry, money) but it's also for your own benefit.