Here's some history for you ... the 9mm cartridge was invented in 1898 and was first used in a German P/08 (AKA Luger) in 1900. It's the oldest smokeless powder pistol cartridge still in use. The cartridge is also known as the 9mm Luger, 9mm Parabellum, 9X19, and 9mm/08. The cartridge wasn't popular in the US until the 1950s when Browning Hi-Powers started selling like hot cakes. The Browning HP was the first high capacity pistol ... also called the Mod 1935, the same year it was introduced.
The US military converted to the 9mm cartridge starting in 1984 using the Beretta M9 as a standard issue pistol. The conversion was done to appease NATO. In the years that followed, most police departments nation wide got caught up in what has been called "the wonder nine years". During this time, most law enforcement agencies dropped revolvers in favor or high capacity 9mm semi-autos. Though very few LEAs have gone back to revolvers, most have dropped the 9mm in favor of the more powerful 40 S&W.
shooter429, Your comment about the 1911 capacity ... up until 1980, all 1911s chambered in 45 ACP had a 7 round magazine capacity plus one in the hole. Those chambered in 38 Super or 9mm Luger had 10+1 capacity. The new style 45 magazines hold 8 rounds +1 in the chamber for a 9 round carry capacity. The S&W Mod 627, which is a N-frame target revolver, has the highest capacity of any 38/357 revolver with a capacity of 8 rounds. The highest capacity revolver meant for a carry gun is a 686P with 7 round capacity. Most 38/357s are 6-shooters .... some are only 5 (ie SP-101).