Humans were designed to live like hunter-gatherers. It was not a pleasant life. It was maladies by disease, famine, violence and fear. Nevertheless, it was a human life. Humans, being intelligent and creative animals, step by step improved their lives, making them less miserable. The result was that human life expectancy constantly raises through history, as well as infant mortality constantly lowers. The apparent consequence is that there is more and more humans on the planet. "Naturally" from time to time the number is reduced by some natural disaster, contagious lethal disease or WAR. Wars became highly structured ways to communicate ancient violent instincts: to the point that those who actually fight do not necessarily have to be aware of the reasons for the fight. War became an industrialized effort to reduce population of another "tribe".
In order to accommodate ever increasing number of humans, we had to develop ways of sharing planet resources, which basically resulted in building ships and plundering "tribes" who did not build ships on time. Over the time the race that built trans- ocean ships first (whites) exterminated, enslaved and contained other three races. Constantly pursuing our natural instinct to better lives of our offspring, we ultimately doomed them. With the increase in population, decrease in planet's resources and the burden of pollution, we were forced to put ourselves in Zoos, the same as we do with our animals. The trade-off of long life and low infant mortality is that every human has less and less territory available. Living in cages makes baboons sad and angry. There is no reason not to believe that it is the same case with humans, too.
Formidable technology we have built to improve our lives and the lives of our kids, assumed a life of its own. It is a while I realized that I was not the only one all the time talking about how my Windows crashed and quoting all six different error messages I got. People seems to spend too much time just making their technology work. And once they succeed they quickly abandon it for the new system. New systems are now created much faster than the majority of population may grasp the previous ones. Yet, everybody buys them. Windows95 spent millions of dollars on add campaign - and the third day in stores a bug was discovered in their program! Now we depend on technology that enabled us to populate the planet over our natural limits. And we have to serve it. Our forebears left us a nice gift: to be slaves to the technology.
The only way, however, is to change our instincts - to make them better in tune with harsh reality. First: why do we desire a longer life - even if this means pushing ourselves into disability, and then living long as a ward of Medicare?! Second: why do we need offspring - if there is already enough people on the planet? Such thinking is not natural - it is actually against our nature: but our reality is not natural and it increasingly becomes against our nature (like the 9-5 sedentary jobs in air-conditioned offices in front of cathode tubes are a non-natural health hazard).
But we will have to change our instincts: with the invention of thermonuclear weapons the war became unpalatable even to the most insensitive generals. After ten thousand years of tireless building and creating, human race FINALLY got scared by one of its horrid creations. The postthermonuclear world therefore developed complex political ways to avoid the big final war. That however just contributes to the problem that we live increasingly in the world that we built for ourselves, but that we are not yet built to live in it. Instead of constantly upgrading our technology, we need to upgrade ourselves. Because our technology became to advanced for us to comprehend it. We need to allow some time for evolution to catch up. Our biological development is much slower than the speed with which our technology develops. The alternative of not waiting is that we are going to end up the dinosaur way: extinct species.
There goes the Capitalism question. Capitalism serves as a main way our social interaction operates. Communism was just one of possible per-mutations. Unsuccesfull. Because it tried to deny that it is basically a modified capitalism. As a more fundamental system than just a social redistribution managment, capitalism's destructability depends on technology and on our own development. Technologically in some places on Earth capitalism may become obsolete already, but the people are not yet ready. They are still driven by their old instincts which were more appropriate in the world for which they were designed initially, but which design their creations soon outgrew. Anyway, we will have to change once again in order to survive our own invincibility on this planet.