The writer of the article is correct. People choosing to borrow ideas from others is sometimes about immediate influence from current styles and tastes, subconscious imitation, habits, ruts... Surely we could have more tire tread patterns on automobiles. But law inforcement needs to keep a manageable data base.
If you look at the possibilities on a lottery drawing and then compare that to the possibilities out there... There are even more than was suggested in this article as I don’t think he was suggesting that he had exhausted every possibility which would include non Western musical scales, etc.
Repeats are a result of human memory- intentional and unintentional.