Functional programming is not hard to learn. Try learn Elixir if you don't believe my word. My observations on why people think functional programming is hard:

Functional programming is not hard to learn. Try learn Elixir if you don't believe my word. My observations on why people think functional programming is hard: 1. They find it hard because they're not learning functional programming, instead, they're learning functional programming, advanced statically typed systems, type classes, and monadic programming altogether. Languages like Haskell fit into this category. It seems the Author took this path (Elm, PureScript, Haskell). 2. The ecosystem is simply not there. Say I just learned Python and there are many meaningful projects I can build to continuously improve my skill. Say I just learned SML, there are not many exciting things to be done. 3. The ecosystem favors power users. Clojure the language is not hard to learn. The ecosystem is not bad at all, both quality and quantity. But: 3.1 I agree that the idea of "libraries over frameworks" seen in Clojure community is better, but when there's less constraint, the responsibility falls on users' shoulders. Working with libraries feels like assemble my own PC. This is also why many people find Vue is easier to learn than React, and Intellij IDEA is easier than Emacs. 3.2 The ideas are novel. It may not be harder to learn, but it takes time. Rails programmer knows what to expect in a Web framework, be it Django or Spring Boot, so when they learn them they just learn like the last 20% of them. But for Clojure I find myself keep learning things like Fulcro and Pathom, the ideas are exciting but it's not ready for the mass. Just imagine how hard it would be to educating "the Algebraic Effects" to React users in 2013. In fact, the React ecosystem has been influenced by ClojureScript/Om, but the React community did pushed hard for the education part. At that time I feel like I came across those buzzword "functional" "reactive" "immutable" "undirectional" in the community every single day - it became such a cliche so that people start absorbing them. Otherwise, functional programming without these problems is easy to learn. Rails programmers can be productive with Phoenix in a matter of days - many of them didn't even bother to learn Elixir or functional programming, they just picked them up along the way.