OMG!!! the brainwashing is much worse than I suspected! Yeesh! Luckily, you have someone here who has seen the light.
Which competition are you talking about, because if you mean this so-called market competition well then that is yet another ploy used by the super-rich to maintain power, along with religion. In case you haven't noticed, there is no stinken competition. They make it appear that there is one but in reality the capitalists maintain this illusion so that they can exploit the masses and horde in lots of money. For example, in the Business journals you will find that most corporate owners are all linked in someway to the US government, if you bother to look deep enough.
Under communism, there will be economic equity because all the modes of production will be owned by the common classes and workers, instead of in the hands of those capitalist scoundrels. Or more specifically, "In communist society, where nobody has one exclusive sphere of activity but each can become accomplished in any branch he wishes, society regulates the general production and thus makes it possible for me to do one thing today and another tomorrow, to hunt in the morning, fish in the afternoon, rear cattle in the evening, criticise after dinner, just as I have a mind, without ever becoming hunter, fisherman, herdsman or critic." -- Karl Marx.
Those bad things happen because all of the societies weren't true communism. Since the time after Stalin's death (the only real communist leader), many have made "reforms" that directly contradicted the revolutionary ideals! If you look at history very carefully, communism allowed the nations who truly adopted it, if only for a time, to rise to the ranks of a super-power along with an enormous rise in living standards. China and the Soviet Union are case examples. And why is that? Because Communism not only allowed equity, which stamped out corruption that is otherwise common in capitalism, but also it was much more efficient as well. There were no bickering corporate leaders fighting among themselves, and society did not have to yield to private interests to get stuff done.
The Soviets collapsed because Gorbachev was way too soft and allowed the dirty capitalists to corrupt it. Nowadays you see the streets of Russia stampeded by organized crime networks.
China is a corrupt country nowadays because Deng Xiopeng decided to drop communism all together in favor of capitalism. While there is still one party rule, they yield to private interests such as those corporate leaders overseas. Under Mao Zedong China was much better off.