You're artificially limited to 1920W(cont. or 2400W short term) on a 20amp circuit and most kettles will barely do 1600W for safety reasons and legacy (houses with old wiring).
It takes an obnoxious amount of time to boil water using an electric kettle in the US. When I go back to EU to visit relatives, I am already drinking tea by the time the kettle boils in the US.