I found this interview intriguing for two reasons. First, I must confess to not realizing that Rand’s philosophy was rooted in the counterfactual belief that people are rational. Every social science (ironically, save mainstream economics) puts human irrationality and inconsistency front and center. Nobel prize winner Herbert Simon studied how woefully limited human cognitive capacities. More Nobels have been awarded for behavioral economics, which (among other things) has catalogued numerous cognitive biases.
Second, the questions that Wallace raises with Rand illustrate how much social values have changed in 50 years.