Fact from fiction, truth from diction. Socialism basically breeds mediocrity. When everything is done for the collective you might as well be like a Star Trek Borg. You are just another cog in the machinery. When everyone has ownership or possesses it, when something really needs to be done everyone is assuming the others will take care of it. On the other end, no one will hardly go the extra yard unless they just want to do it for themselves, do something more, or better has no meaning because you will get no more recognition than one who just did the minimum.
Communism is about as bad. When the government owns everything there is still no reason to rise above mediocrity. You are guaranteed a job and a salary so one knows they are covered. I suspect under communism what job you have is not what job you want but where your skills best serve the nation, which could lead to unhappy workers who are less industrious.
With capitalism the individual has a chance to be his own boss, have his own business. Therefore, they have a stake in their future and their own direction. The added effort they put in has the potential to manifest itself into higher profits. Under capitalism one has the chance of doing what one likes for the good of oneself. Healthy competition leads to innovation and greater efficiency. Because the bottom line is the responsibility of the business owner to rise above mediocrity and have a better product or service is a desired goal. For having better service or goods means more customers, which equals larger profits.