Because it didn't. Many of us disagree with both the assigned start and end of the period. (See multiple other threads.) For example, some of us see Frank Miller's work on Daredevil and Denny O'Neil becoming the editor at Marvel as the start of the CA (specifically issue #168 in January 1981, when Miller took over as both writer and artist.) On the end point, some hold the Death of Superman as the end of the CA. Personally, I think that's arbitrary and convenient.
But the start of Image Comics was similar to the change in film studios when United Artists began under Charlie Chaplin, "The inmates are taking over the asylum." McFarlane and others did more or less the same thing at Image and for essentially the same reasons. Still that makes the CA an 11-year span, which comparatively is not "short."
The only aspect that makes the CA seem "short" is the seeming reluctance and apprehension of breaking up the current 26-year period referred to as the "Modern Age."
Coincidentally, see D ick O.'s Post here.
While Digital Age may be a good suggestion, we might even consider the "Plastic Age" starting with the advent of CGC, and the soon to be antiquated commercial practice of creating a trading commodity enclosed in plastic.