Kettles are also use more power, the average kettle is 2800W. That sort of power usage just isn't possible in a US kitchen. I just checked ours, it's lowest range is 2300W. The average US kettle is 1500W.
So that explains why people outside of the US think that kettles are so fast and convenient, but people in the US do not think they are faster than a pot on the stove or the microwave.
How long does it take to boil 1 liter of water in a kettle where you all live? I'm in the US, and I live at 6000 feet above sea level (so water boils at a lower temperature, but because of the thinner atmosphere, it takes longer to get to that point, and it takes about 10% longer to bake and cook things in the oven than the instructions listed in cookbooks).
I'll be scientific and go boil a liter of water in my kettle and time it and get back to you.