2 kW @ 120 V is 16.7 A, which exceeds the 15 A limit on most household wiring in North America. To be able to achieve that you’d need to get a 20 A rated circuit installed by an electrician which means pulling out and replacing the wiring with a heavier gauge.

The advantage of 240 V rating in the UK is that you can draw more power with less current, so you don’t need the wiring to be so heavy for a high power appliance like a kettle.