Capitalism requires periodic socialistic intervention in order to survive. It is the parasitical nihilistic nature of capitalism that it needs injections of socialism in order to live, while socialism does not need capitalism at all.
Pure capitalism cannot exist, simply because all instances of pure capitalism would eventually evolve into forms of socialism. The natural tendency of capitalism, if unchecked by socialistic intervention, is to precipitate monopolies, which grow and agglomerate, until, if taken to the logical conclusion, there is one all-embracing monopoly, and this would be, for all practical purposes, a form of socialism. Capitalism, in and of itself, cannot exist, and is nothing more than an defective distortion of socialism.
Marx was not the only socialist thinker, and he was not infallible. He was incorrect when he stated that socialism needs the wealth accumulated by capitalism in order to come into existence. In fact, quite the opposite is true, it was the common wealth of the proto-socialist Catholic monasteries which, when robbed by the Reformers, provided the initial capital which helped to launch capitalism. It is no accident that those regions of Europe which separated themselves from the socialistic influence of medieval Catholicism, and which confiscated monastic properties and converted them into private ownership, are the same regions of Europe which shortly thereafter became the leaders of world capitalism.