The facts of history don’t agree with you. First off, as soon as political power merges with the economic system, we have crony capitalism, we have politicians and bureaucrats interfering in capitalist markets; we no longer have capitalism.
It isn’t capitalism that causes this; it is the desire of company owners to be rid of competition and enjoy favorable laws and regulations, it is the desire of politicians to have companies advance political agendas and underwrite their reelections and maintain themselves in power that is the cause. All of this is contrary to capitalism, but are features of fascism. Fascism and socialism corrupts capitalism, they do not spring from capitalism.
You perhaps don’t know that the originators of Fascism, in Mussolini’s Italy, were all socialists and communists. You have it exactly backwards — capitalism uses the marketplace to determine business winners and losers; Fascism and the other flavors of socialism use the power of government to determine business winners and loser. That is why big corporations find socialism so attractive; they have the money and contacts to ingratiate themselves with politicians, and thereby ensure the demise of competitors and favorable laws and regulations. They are thereby guaranteed big profits and the politicians are guaranteed power.
You should perhaps read the story of Argentina. About a hundred years ago, Argentina under capitalism was as rich as America (on a per capita basis). Then they freely elected a socialist government. Slowly at first, and then faster, Argentina declined until it was a total basket case. And still is. [http://applet-magic.com/argentinatanoira2.htm] and also here [http://directorblue.blogspot.com/2009/11/dont-cry-for-me-america.html].
It is quite easy to destroy capitalism and all its benefits, just elect a socialist government. But it is pretty much a one way street. Better be sure it’s what you really want, because it is devilish difficult to get capitalism back.