Your list also implies that average level of tech performance has also proven to be acceptable.
Err what? all those devices are essentially bleeding cutting edge. Unless you're talking strictly for games, which is not the main reason people buy any of those (even then, they actually are bleeding edge for mobile as Chef pointed out!).
Apple in particular surprises me how much they push graphics and performance, probably too their credit, when "good enough" seems like it would suffice for iDevices. The iPhone 4S may sport a ancient 3.5" screen, but at the time of it's release the GPU and chipset was absolutely cutting edge even trumping all androids, as all iPhones.