This may be true, though other philosophers have hypothesized that there's no way to even know whether objective reality exists since we are trapped in subjectively perceiving bodies. How does Ms. Rand answer this challenge? She doesn't. I guess we have to take it on faith (oh wait, she doesn't have any of that since it's not rational).
I believe it was Philip K. Dick who said something to the effect of "reality is that which continues to exist regardless of whether or not you believe it." After all, I think that if a tiger is gnawing on my thigh one can objectively state that there is, indeed, a tiger gnawing on my thigh and perhaps I should do something about it. Heck, you could probably even get a consensus from a group that being eaten by a tiger is a genuinely bad thing. As for those philosophers who hypothesize that objective reality can't be known, I have come to the general conclusion that they're too busy splitting philosophical hairs to offer something actually useful in one's everyday life.
Why exactly? Why is the pursuit of his own rational self-interest morally better than balancing the pursuit of rational self-interest with the interest of others?
Because there is fundamentally no need to "balance" one's own rational interest with that of others. Pursuing your own rational self-interest allows others to pursue their own lives rather than being forced to help you or being exploited by you.
If you were late for a very important meeting and you saw a old woman with a cane fall into the street, would you stop and help her up, help her home even? Even if it made you miss your meeting? Where's the rational self-interest in helping the old lady? Which action do you think is more "moral" (stepping over her or helping her)? Something doesn't jive here.
Evidently you've not read "The Virtue of Selfishness." In that book Rand offers a better theoretical scenario and solution. Her scenario involves sacrificing one's life for a loved one. If you would not want to live in a world devoid of that loved one, if letting them die would cause you no end of grief, then sacrificing yourself for their life is not philosophically inconsistent with Objectivism. Likewise, if old ladies falling down in the street causes you to be unhappy then there is nothing wrong with helping them up, even if it means you are late to your meeting.
The ideal political-economic system is laissez-faire capitalism...
Hunh? Where does this come from? How the heck does this follow from accepting an objective reality? How does rational self-interest being the highest moral purpose of life follow from accepting an objective reality? They don't. Nothing is ever tied together. For someone that deifies reason, she's sorely lacking in formal logic.
yes, actually, they do. Rand claimed to have derived some of this from the natural world. A form of life will generally act to preserve its continued existence*. In other words, animals will act in their own self-interest. Man, being one form of life will do likewise. However, since humans possess the ability to think rationally they should also recognize that other humans have just as much right to exist as they do and that it is in their rational self-interest to allow others to continue to exist.
Rand's observations about laissez-faire capitalism derive from this mindset. It was her belief that laissez-faire capitalism was the one system that allows humans to live a life of rational self-interest. After all, in a laissez-fair system one is free to engage or refrain from interacting in any given transaction. Capitalism is founded on the principle that two parties can enter into a deal and both will come out better off. Personally, I think she's right, and it boggles my mind that there are people who don't see this as being blatantly self-evident.
*Rand claimed all animals. Not being a naturalist, I don't think she was aware of say, the mating habits of the Praying Mantis. For the sake of argument, allow us to limit the statement to mammals.
Accusations of being a Randroid in 5...4...3..