Bear with me please. I am a classical guitar student who is teaching himself keyboard for composition purposes, and I've gained some appreciation for the keyboard. Some pieces I've struggled with on guitar are at a very beginner level on the piano, it is superior for polyphonic music to the guitar for many reasons which are probably obvious.
I think some would argue that the piano is more limited in dynamics though, you can only control duration and loudness. Whereas on the guitar you can slide notes, hammer, change between a dolce timbre and an aspro, and probably lots of other things I don't know about.
But the electric keyboard is a very versatile instrument. Portable, can make pretty realistic synths of real instruments, and getting cheaper by the year. There's sliders built in, pedal controls, etc. Just take a look at this ROLI seaboard ad for a quick demonstration: [Link]
Will the electric keyboard, in the future, dominate the music industry/production/etc. and fade interest in learning non-keyboard instruments?