Therefore observing that a language or paradigm is popular or unpopular does not say anything about whether it is good or bad. JavaScript is the most popular language in the world. If Netscape had decided to use a Scheme-like language or a BASIC-like language it would still be the most popular language in the world. So paradigm has nothing to do with it.
Functional programming is less popular because no major successful platform has adopted a functional language as the preferred language.
I don't buy that functional languages are unpopular because they are unintuitive. Losts of stuff in JavaScript is highly unintuitive. It didn't prevent it from becoming the most popular language in the world. People will learn what they need to learn to get the job done.