Regardless of what you're able to see, certain types of shooters were in fact a huge part of the arcade. Asteroids was probably the first major shooter. Then you have games like Time Crisis, Terminator 2, House of the Dead to name a few that were in virtually every arcade all over the world and on every cruise ship.
I get it, but when I see multiplayer shooters the only thing thet comes to mind is Counter Strike (granted, it's far from the first online shooter, as online multiplayer on PC shooters were a thing since the 90's)
Even if the genre born in arcades its selling point lies on online multiplayer, this used to be a PC game feature. Just like RPG born in PCs, but evolved on their own way