Donnywithana had two main problems, based on the premise: An Objectivist society is a meritocracy.
Problem one: Inheritance conflicts with meritocracy.
Problem two: Monopolies exists in an Objectivist society - wich conflicts with the idea that this society is a meritocracy.
Objectivism proposes a society based on individual rights. Primarily, the political system based on individual rights is concerned not with merit, but with justice.
If all men are rational, this will lead to a meritocracy. But this is secondary, and even merit can be interpreted differently, by different men.
It is important to note that, once someone acquires property, the sole responsibility for dispensing with that property lies with the owner, whether or not the beneficiary has merit. But merit, in this case, is determined by the benefactor - It is not just to force the benefactor to choose to make decisions regarding the distribution of property after death, using someone else's values. This leaves the benefactor free to make decisions as he sees fit; on non-political, non-economic merit, such as the familial value a father places in a son, if he so chooses. This, I believe, addresses your first problem.
Your second problem regarding the monopoly, is based on another the false premise: economic pressure is equivalent to political pressure. In other words, business strategies are tantamount to coercion at gunpoint.
True coercive monopolies exist only by government sanction. The only way a company can use force to expand and control it's market share is with government permission, or through government neglect. In an Objectivist society, coercion is banned from economic activity.
Example: While one person might be disappointed that he can't sell the best chairs at a high price because of a larger companies business tactics, the consumer will still benefit from cheaper chairs. Isn't a company that sells cheap furniture "getting by on it's merits?" Regardless of how you answer this question, nobody's rights are being violated, and people still have the opportunity to buy higher priced chairs of better quality if they want to.
I also suggest reading Objectivist material on the nature of market value. I gave a quick scan of Capitalism: The Unknown Ideal but I couldn't find it. If anyone could find that reference it could be helpful for Donny.
-Edited for punctuation and clarity.