Well, here it is!
It's a technology revolution! Consider these facts:
1. Never needs tuning.
2. Build in metronome.
3. Plays more than one sound so well that only an expert can tell the difference (if the sound is played properly!) thus not limiting your creativity nor requiring you to learn (and OWN) all those other instruments.
4. You can plug headphones into so nobody can hear you play or practice.
Amazing. But you can't get these things on any acoustic piano, only on a keyboard. I'd say that the keyboard was an advance over the acoustic piano.
Hey, all that the acoustic piano has going for it is simplicity of play. And that can be fixed for keyboards pretty easily.
Makes sense, however. The acoustic piano was very high tech - back in the early 1700's! Keyboards are current technology
