How does the line, “That there should be anything more to it than that was a thought that never entered his head” contribute to the characterization of the man in the story?

That it should be more important than that was a thought that never entered his head.

This quote supports the man's inability to see beyond his own knowledge. He is thinking factually.... not considering things outside the box..... the things that can interfere with or ruin even the best laid plans.