I think the author gives us a hint about what is ordinary:

"They tend not to be representations of noble ambition, or of a classical or romantic vision of how human beings might achieve greatness."

As an aside and don't take this personally - perhaps your question was actually "I am sure what they mean but I'm trying to disagree" ? Or perhaps it's "I wouldn't be able to make the decision if I had to do it"? I never know about this use of language. It's like asking "I don't understand why someone would vote for X" when the question is really about them actually understanding and wanting to state ones opposition to it? That type of question is not asking the reader "help me understand", right? It's confusing to me.