They haven't grown up.
I greatly enjoyed The Fountainhead and Atlas Shrugged and a couple of other of her books. I was in my early-mid-20s when I read them.
The books appeal to guys who see problems in the world, who wonder why those with power don't make the "obviously correct" choices. She plucks the "self-reliant" "rugged-individualist" and "young hard-working rebel" and "rational" strings really, really hard and tries to make a consistent world out of it. It appeals to people who want simple answers in a complex world, but who reject religion as being for weak-minded people. It appeals to people who have seen idiots and "weak" people cause problems in their lives. It appeals to people who believe they are more special than almost everyone else.
She was shaped by her childhood and early life in the early Soviet Union (hi Mike!). (She came to the US in 1926.) She was telling a story in those books. She was trying to use illustrate how the world "might and ought to be". (She loved Victor Hugo and Jean Valjean because of the way Hugo could tell a story through him.) Yes, she argued forcefully that she had it all figured out, but it became a religion later on. She loved Nathaniel Branden as someone who could "always speak for me", then turned on him as the jealous lover she was (of course, she did it "rationally" in her eyes).
Of course, even if some elements of her "philosophy" make some sense, it was a cartoon. As others have asked, "who cleans the toilets in Galt's Gulch?". An ideal society may work by everyone rationally trading dollars for manual labor or the sweat of their brow or gadgets they have made. But, society isn't ideal, and, as you say, people are duplicitous. Some will enslave their weaker compatriots - even in this day and age, and even in a city like New York.
Insular intelligence that ignores humanity in favor of some cartoon idealized individual isn't something that will save the world. It can destroy much of what we have learned about building a society that works for the great majority (including the intelligent and the powerful).
People who are devoted Any Ayn Rand fans more than, say, 5 years after they read Atlas Shrugged have something wrong with their emotional development. They haven't finished growing up. IMHO, of course.
My $0.02.
[edit:] tyops.
Cheers,
Scott.