It took a few years and lots of supporting technology, but the Macintosh did, in fact, kill the traditional typesetting/printing industry, by putting page composition tools in the hands of graphic designers. Prior to desktop publishing, the mechanical and creative sides of page composition were two completely different processes.
Why is this important? Well, for one thing we're starting to see digital technology take over what's left of the printing industry. Inkjet and toner-based printing processes are making it possible for more printing to take place on site where it is being used. This will only increase as technology gets more sophisticated.
But will we see the death of the commercial printing industry the way we saw the death of the typesetting industry? Doc thinks there will always be the need for large-volume commercial printing, but more and more printing output is going to take place at the point of use, or as part of a manufacturing process (as with packaging). Seems the definition of printing may change once again.