The trick in the videos is to use a narrow vessel. I suspect that if they used a bigger pot or, say, a kettle it would not be as impressive. In the second video it's a gas stove from Thermador (you can tell by the star-shaped burner) witch is usually 5K watt burners in the front. I don't know what induction stove they have but seeing that they have multiple "burners" that come together to 10-11K watt max, I'd say it's 3K watt tops. The gas stove is losing way more than 50% heat to be almost twice slower, which is not a surprise since the pot is smaller than the burner.