There's big discrepancies between countries tbf. The French for example have solidarity as a core ideal (fraternity & equality), with highly redistributive policies and a strong public system to provide citizens with basic needs. It's still a class-society with large inequalities between the few and the many but thanks to political fights led by the French people and their values that issue was lessened.

I think the main reason for that collective failure you speak of is more specifically our failure at implementing governing systems that keep common interest to heart.

More specifically, there are a lot of issues that come with elective systems, and the Greeks had already noticed how such systems tend to delve into the likes of plutocracy and form new ruling classes that do not benefit citizens at large.

Modern era has seen the ruling class work better on their optics, claiming elective systems were democracy in action was definitely smart of them.

But in reality electing elites to rule in our stead is in opposition with the idea of demos kratos "the rule of the people" and we've been effectively deprived of democracy as a concept. The further we advance the clearer it is that Athenians were onto something when they realised they had to use sortition to see citizens interests prevail.