9mm vs more effective rounds. Probably due to cost. Cost of ammunition and cost of training for the run of the mill agent. Easy to train people for the 9mm.

Same for the local coppers. Most never use their firearm in the field. Many are hopeless with a handgun. Not seen as a big priority. The good ones practice and shoot in their own time. I remember one incident when three dozen shots were fired by several police in the old .38 days, some hits, at an assailant in the open on a oval.

Us poor fools in Australia are mostly restricted to the lesser calibres, such as the 9mm, but can use the .38 Super and .357 SIG. The .40's and .45's etc can be owned if one shoots such a sport as metallic silhouette. Forget about anything for civilian self defence ...