Capitalism contains the seeds of its own destruction. "the invisible hand" sounds good and all, but the problem is that if the owners of capital control the profits produced by the mobilization of capital, then money and power will inevitably become concentrated enough that those capitalists both benefit from and become capable of restricting market freedom. The idea that free markets are a stable state of affairs is a faulty assumption.
[edit to note: this is only one of the many internal contradictions of capitalism, but the most relevant to your argument imo]
[edit to note: this is only one of the many internal contradictions of capitalism, but the most relevant to your argument imo]