Your points make little sense regarding human nature.

In a world of houndeds saving one is a necessary thing for the groups survival.

In a world of Billions, you just replace a lost one with the next, just like we replace broken parts in a Mashine, its a unfortunate truth that everyone is replaceable now, even if we hypothetically clean a entire country out of existence, it would barely impact the rest of humanity, shure it would be in the news a few days, but after that... I doubt you feel actually sorry when hearing or even seeing death to strangers, same with misery, you might think about it for a few weeks, but it goes away and your life goes on. Thats why communism is absolutely impossible.

What is possible is a social market economy, wich is a democratic system but with limitations on capitalistic problems to ensure that even the lowest of society aren't treated like human garbage. But even that is hard to implement in places like China or USA.

There is no perfection, especially in Politics, there will always be pros and cons to everything.

The Way we chose and will choose will always be paved with corpses and misery. It will never change unless we change the human itself.