I wonder if it might be a case of learing how to do relationships well. I'm sure there are people who dated many people in their 20's who went on to discover what it meant to have an ethically non-monogamous relationship meant. There might be a difference in the way it is done but if these 20-somethings now have a term for how they feel they might be more likely to seek out the resources on how to be compassionate and open towards their partners.
Your 20's are a time to learn how to be in relationships in whatever form those relationships take. There aren't a whole lot of people who do monogamy well in their 20's either (think "If you don't know what's wrong then I'm not going to tell you").
Everything will be ok in the end. If it's not ok it's not the end.