I know I'm late to this party but....I've always suspected that one of the reasons that electric kettles aren't as popular here in the US is because the electric current is lower. With the higher electric current, the kettles are much faster in the UK than boiling water on the stove but in the US, it's not really a huge time saver compared to the stove. It's like blow dryers being more powerful elsewhere in the world than in the US (or I've always thought, at least) and drying hair faster because of the more powerful electricity.
I do now have an electric kettle here in the US but it's because I have a very anemic electric stove. I pretty much just use it for boiling water for coffee, tea and pasta.