"All non-trivial abstractions, to some degree, are leaky." - Joel Spolsky

> In my experience, learning OO design patterns was substantially more difficult than learning algebra, but I think this is mainly due to how CS education is carried out in many universities.

You supported my argument. In addition to this, there are many code academies that pump out graduates with almost no mathematical foundation work. Until that changes, functional languages will always take the back seat.