I suspect there are more Glocks and 1911s in the hands of American shooters than other handgun types, so you're probably going to see a lot of those in any range video.
What is popular at IDPA and USPSA nationals isn't necessarily going to be indicative of what you see at the local level, because so few people shoot nationals; you see what the champions and contenders are shooting, and at the highest level it's often what sponsors provide, rather than what a given shooter would shoot on their own dime.
Early in my USPSA shooting days, all the champions and contenders seemed to shoot SVI pistols, but I was in the sport for ten years before I knew anyone who'd bought a SVI pistol with their own money.
At the local level, everyone bought STI.