SISOMO - It's all about RGB

I just got my hands on an interesting book: SISOMO by Kevin Roberts, CEO worldwide of Saatchi & Saatchi.
Roberts describes, how the screen is now the most prominent media in our daily lifes. Screens are ubiquitous, omni present and manifold in form, size and function.
Enter sisomo—sight, sound, and motion, the combination that made television the most powerful selling tool ever invented.
I was instantly reminded of an exhibition, I visited in the late 90ies in Oberhausen. It was called Der Traum vom Sehen / dream to see and was accompagnied by a thorough documentation of german tv history. Some pictures of that exhibition can be seen here: Triad, Berlin. That exhibition used only a few but very accentuated highlights of german tv history to indulge the associated memories.
But if we can agree, that screen media in all its variations is now the presentation form that gets our very most attention, why is there still so much media produced in CMYK?
Given, CMYK is needed for print, but to store and archive CMYK leads to a qualitative dead end.