If JS + HTML + CSS is all they know then I really don't want their software running on my machine.
And the beauty of Electron is that you can still write all your actual logic in C/C++ and use Node's FFI to bind it to your UI.
(Qt is transitioning to the same model with its HTML+JS based Qt Quick orchestrated from native code; but it's far less production ready than Electron right now.)
A developer that only knows js is unlikely to be competent (beginners aside).
Oh, don't get me started…
Yes, that's a problem. But Electron can hardly be blamed for it. They'd use XULRunner if it didn't.