Yeah any ideology that's dependent on nobody prioritizing their self interest over society's best interest isn't going to work.

But that doesn't mean a functional society isn't possible. We're living in one right now. Sure there are a lot of improvements needed, but improvement is possible.

Utopia actually translates to "no place". Only fictional people can achieve a utopia. Real life functional societies with real people are an iterative process. Make improvements, some asshole finds a loophole to exploit, make more improvements to prevent assholes from exploiting the system. Repeat. Do that over and over again, vote in elections over and over again to move society a little closer, inch by inch, a little closer to the ideal, even when the ideal isn't actually possible.

Societies aren't created by intelligent design, they're a product of evolution. But that evolution can be guided by the people that vote. Democracy isn't something that's ideal, it's a grind. You're never going to be living in an ideal society, but if you try you can make the society you live in a little better.