It’s proven that the things that give you pleasure eventually give less and less dopamine as you get used to it. Think about being in love, eventually just being around the person you love isn’t going to give you the same good feelings as that great first date did. Still good feelings, but not the same. So how do we as a society continue to chase that high when doing good for other people in our society becomes commonplace and everyday? 
So I don’t think it’s chemical. I don’t think world leaders are enacting laws and policies that benefit the public good because they get personal warm fuzzies from it, or because they think the public is going to get a good feeling from it. If you’re going to go with the chemical thing, then the argument could be that the more stable society is, the more free time everyone has to pursue leisure activities and hobbies that do give those good feeling highs, and that’s why people collectively want a utopia state where no one’s starving and has to worry about just survival