The problem is that electric kettles in America are slow as fuck, which I assume is due to the 110V power supply.
Go somewhere with 240V and two things happen: (a) you're far more likely to die of electrocution in your own house and (b) you can get a decent tea kettle.
A 3kw heating element is a 3kw heating element at whatever voltage it operates, so I suspect that there may be a limit on the current that domestic appliances can use in US kitchens.
At 110v you would be looking at 27 Amps which may be a little high. I had not thought this one through before, thanks.
In case grandparent is too elliptical for some readers --
The maximum current determines how thick the wires have to be. Since power (ability to heat or do other work in one unit of time) == current * voltage, doubling the voltage doubles the amount of power a wire of a given thickness can deliver.
Well done, I should have emphasised the principal.
Looks like the maximum power that a US kettle can produce is 110 * 20 = 2200 watts, so will take about 3000 * 2200 = 1.36 or 36% longer than an EU kettle to boil.
Microwaves have their own problems - they can superheat water without boiling it, which will then explode in a fury of scalding foam as soon as you jostle it.
They're also frequently mounted overhead, where it's more dangerous to retrieve a mug or big Pyrex cup. Contrast that with the kettle which has that little flap over the spout and is spill resistant.
Go somewhere with 240V and two things happen: (a) you're far more likely to die of electrocution in your own house and (b) you can get a decent tea kettle.