Objectivist epistemology holds reason as the only absolute and ethics as pursuing one’s rational self-interest and laissez-faire capitalism for politics.
I fully agree and believe that a laissez-faire capitalistic society is the best form of society for humans - only if we behave rationally. And that is the problem. Not everyone is rational and uses their reasoning skills properly. Won’t these particular group of irrational people upset the laissez-faire capitalistic society? How do we address this group of people? And if we can’t address this group of people, if we can’t rationalize this group of irrational people, doesn’t it mean that a laissez-faire society is not that wholly workable? And maybe, a capitalistic society with a little form of government intervention (to address this group of irrational people) is more suitable?
Those who violate other people’s rights will be dealt with by the Government. This is the sole purpose of Government in a laissez-faire capitalistic society.
I think the OP is trying to suggest that the economic system, capitalism, is untenable where political power is in the hands of those who wish to dismantle rights rather than protect them. Of course, the question is somewhat moot because the capitalists would need to wrest political control from those same people before they can establish capitalism.
Now, if it were the case that the majority of the population supported capitalism and individual rights, they would be able to establish a system that would defend those rights against the would-be anarchists, theocrats, communists, etc.