Why do computers look like this anyway?

I have now sent my wife 4 different stills of this video. Presents an area of computer history I'm familiar with--so not necessarily learning much--but high quality and done with incredible rizz. I can't believe this person's only other video is "Every Tim Allen Grunt At The Same Time."

I feel this might be a nice companion to "Are we really going to use the same Desktop UX forever?"