I think the narrator believes that the men he is talking about lacked vision to anticipate future problems and courageously deal with the consequences ie they did not actively or proactively deal with life but on the contrary allowed themselves to be victims of circumstance. Re the word "I" I think he means that they did not realize the power they had to change the course of events.
Instead of studying medicine, law, or theory, he decided to study necromancy.
