The type of developer that only knows one language of any kind is in the same boat. Electron is popular because folks can write products at a faster pace than they could in other toolkits and languages. Being unproductive and fighting your tooling is not a sign of competency, nor is it a rite of passage. If folks can write apps faster in Java or Rust (which I love writing, by the way), I'm sure Electron would not have the adoption curve it does. Nothing to do with only knowing one language.
A developer that only knows js is unlikely to be competent (beginners aside).