Uncharted-franchise has sold more than 28 million copies & U4 Poll

[FentonCrackshell]

I never understand how a gem like Uncharted 4 releases on a console and only sells around 7 million on a console with 40 million install base. I mean, I know not everyone is going to play the same games, but I'd think a top notch title like this one would move more units with such a base.