Most people in the US don't make tea much, and just use an automatic drip machine or a keurig for coffee, so of course they don't have a kettle.
We have one, but it's because we drink more tea than most Americans, and since we have it for that, it's space-saving for me to also use it for pourover coffee (rather than having a drip machine).
At least, I can totally see how it would seem as such to anyone from the UK (and most of the world).
For my part, despite working at it for years, I still don't really like cheap tea (the stuff I could actually afford to drink every day, and that can be found without seeking out rare-in-the-US tea shops or ordering online), though higher-end tea is really good.
We drink a ton of iced tea, but that's easily made on the stovetop in a large pot, and can be bought in gallon-quantities at the grocery store. Having a kettle doesn't improve iced-tea-making very much.
[EDIT] Part of it may be that we drink on-the-go more than other countries. Just a guess, but might be true. Iced tea and coffee (hot or cold) are both much better for that than hot tea—one doesn't usually make a thermos-full of hot tea and drink it straight from the thermos, I'd expect (but maybe I'm wrong?) but that's normal for coffee.
They're easier to find these days but still rare. If you ask for a hot tea at a restaurant, you'll often get a suspicious-looking teabag that has spent at least 6 months in the cupboard (iced is more available). I'm sure you can guess at the quality of most of the teas in an American grocery store; I usually wind up ordering from specialty tea shops instead.
There is no way an electric stove is quicker than a gas stove. I did a quick google search and a standard gas stove on high is 12,000-18,000 BTU, which is 3.5-5.4kw.
It's a one-hour-plus video of someone literally boiling water, so there may be issues with the testing setup that I skipped over.
Don't know where the heat is being lost, but an electric kettle is significantly faster despite its lower energy.
On gas? Around the sides of the vessel, bound for the ceiling.
The origin story for the boiling water tap is powdered instant soup, which isn't quite instant without instant boiling water... :)