Then the 9mm became popular only to be supplanted for a short while by the .40 because of a shooting in Miami. We then went very briefly to the 10mm before going back to the .45 and then back around to the 9mm.
Now we are in the age of the pocket guns, of various sizes and no doubt we will transition back to the .40 or .45? No.
Frankly we are living in an age where all of the above fit in their own respective place. And besides, better to own two or more of each.