I find this topic very interesting. To be honest, until only a few years ago, I thought a kettle of some description was as standard as a microwave: sure, some people might not have one, but they are very much in the minority. DH and I have between us lived in four countries, and we've traveled a bit and visited several more countries. Eventually, we once found ourselves in the USA in a decent enough hotel which had no kettle. We were stunned: how would guests make tea? It was an international hotel, so although coffee was more the norm in the USA, they were billing themselves as a place that catered to what was more the standard in other countries. We asked at the front desk if they had one we could perhaps use, and the guy didn't seem to know what a kettle even was. He kept saying, "Oh, do you mean a coffee machine?"
In the end, Google helped us boil water safely in the coffee maker (we didn't want to break it by not using it as it was intended) and we had tea that way.
I grew up in Australia, where every home I've been in has had a kettle of some sort. Most electric. In nearly every country I've visited, kettles are the norm. So until we discovered the lack of kettles in the USA, I would have ubiquitously associated kettles with developed countries. Now I know better
But it was certainly a strange thing to discover! Here in Singapore, we have a super fancy kettle which boils water in four seconds flat. It's unreasonably fun to use.