Thank you for the detailed response. In my circles that judge books, I'd actually expect more sympathy for Rand than Marx (or Piketty), so I think mileage varies.
To me, it seems that what you describe as the 'key idea' of Atlas Shrugged is actually two separate ideas; 'individual is more important than the state', and 'sacrifice of a few innocents for the many is not morally valid'. Leaving the individual aside for the moment, for the second idea, how do you reconcile the reasonable notion of not sacrificing innocents for the many with cases where the many will suffer unfairly (e.g. the Trolley Problem [1]) when it is in your power to act?