This logic could be applied to every major advancement throughout human history. Yet here we are. Ideas grow and spread. We no longer accept slavery. Is this universal? No. Better than it’s ever been? Yes. The spread of ideas is the only way that broader collaboration can ever happen.
For a species so self interested, we’ve managed to invent the medium that I’m typing this comment from, and that in itself is proof that self interest led to global advancements that achieved more than any single group of humans could achieve by themselves.
And self interested or not, we’re still fundamentally a social species, clearly capable of understanding that survival of the collective is critical to our own survival.
If you don’t grow your own food, if you drive a car or ride a bus, live in a building you didn’t construct, stopped at a red light, baked food in an oven, and on the list goes, you are already intrinsically linked to and dependent on the cooperation of a large web of other people. And it’s in your own self interest to preserve the conditions that allow that web of support to continue.
Whether one stops to consider/acknowledge this is another question, but the “collective we” is already completely interdependent, and acting in a self interested manner is modulated by education.
So what is helpful? Hopefully a growing awareness of the situations we face and the realities of what we’re doing as a species. When awareness grows, self interested behavior starts achieving new/different results. History proves this.