I am not sure I if I can speak to that in general but personally I discovered functional programming late. Object oriented programming was all the rage when I got initiated and that is all that was taught in colleges.
IMO the ELM architecture only works with pure functions. It doesn't work with languages which cannot provide this compile time guarantee. Also functional programming needs a different mindset / training. You won't benefit from it until you understand what it actually brings to the table (and what it leaves out).
> Some common design patterns are so flexible that if you really implemented them in full generality as, say, some library function, its interface would be so complex that it likely wouldn't be a net win
Then I would say you have not arrived at the optimal solution. Keep looking.