If you practice domain driven design, you can always start out isolated projects or even just new modules if your code is sufficiently modularized. I started out by making a new library/module with Ramda, and then it's consumed via a function call that anyone programming in any style can use.

Agreed that functional patterns can be hard to understand if you don't know the patterns, but if you do know them they are much easier to understand and reason about the code. It's a long term investment, and one that frankly I believe will be inevitable as more and more people start doing programming work.