If Conservatism means to conserve traditional social institutions

It doesn't, not entirely anyway. That's characterization meant to create division and derision. Only certain types of conservatives actively seek to preserve social institutions simply for the sake of preserving them. For most of them, preserving a social institution is a side effect of another viewpoint which would cause the traditional institution to appear more effective, efficient, or advantageous for society on the whole. Even still, you'll often find conservatives actively seeking to destroy traditional social institutions for the sake of achieving a more laudable government (such as redefining marriage in contractual terms and getting government to cease recognition of it at all).

You've also got to realize that the "freedom of association" is among the most important part of conservative ideology. Many liberals like to think this is just a justification for racism, but it isn't. It's a blanketing ideology that encompasses many actions conservatives believe are an extension of basic human rights. Take boycotts. Boycotts are a form of freedom of association. You choose not to associate with a merchant. Take school choice. You choose not to associate with a bad school unless they improve. Take exclusive organizations like the Congressional Black Caucus. Again, freedom of association. Freedom of association to conservatives is a very large, umbrella-like idea that covers many good and some bad behaviors, and it's generally believed by conservatives that like most things in life you must take the bad with the good because the good far outweighs the bad. The freedom to hire only white people is a freedom that brings consequences, consequences that are born of freedom of association as well, the boycott and market competition. The consumer chooses not to associate with the merchant, and a large chunk of the labor force chooses not to as well because of that practice. The merchant is free. The consumer is free. The laborer is free. Everyone is free.

So, you have to realize that capitalism is not embedded into conservatism. There's actually conservatives who don't think it is a good system. Capitalism is just the economic form that most conservatives believe can provide the balance of freedom, choice, and consequence that they seek. If another form of economy arose that could do it better, conservatives would abandon capitalism altogether. But, capitalism is, at the moment, the least restrictive economic form, it is where the libertarian-minded and socially conservative people fall to.