Trying to think of.... popular general use pistol calibers that were NOT chosen by any military or police agencies first.
.22 LR? Most popular of all time, but only used by military in training.... I think.
.32 acp? Military and police.
.380/9mm Kurz? Military and police.
9mm/9mm Luger/9x19mm? Military and police.
.38 Special? Police.
.357 Magnum? Police.
.45acp? Military and police.
I think most other calibers don't fit the 'general and popular' parameters, but I'm willing to be discussed at.
What brought this to mind is the new Federal 30 Super. It looks interesting, for reasons, but I wonder how deep the market is for it. The .327 Federal and the .32 H&R Magnum look pretty cool too, but they are clearly footnotes in the big book of pistol cartridges.