This goes on for about 10 million years. We end up with 500 people owning half the planet. If you believe the ideological priests of capitalism, this is great. Those 500 people worked so hard and were so smart that they deserve half of all the wealth on the planet. Capitalism isn't a bad system.
Communism sounds great in the abstract, but nobody's succeeded in making it work in practice.
There are two big things wrong with it. First of all, it requires a high degree of government control over everybody's lives. Secondly, it reduces the incentives for people to work hard and produce things of value. It's unfortunate, but human beings don't have a great deal of self-discipline. Without a good reason to work hard, we won't.