Did you miss the part about how it's still the fastest way to boil water? Yes yes, it's slower than yours, we're all jealous. Even still, we would all have electric kettles if we needed to boil water all that often because it's faster than anything else we have. But:

• People don't make pasta or rice every day, and even when you do you usually have plenty of time for it to come to a boil while you're chopping or stirring or whatever. People who do make rice that often typically use a rice cooker.
• You can't really boil enough water in a kettle to cook potatoes or vegetables or anything else.
• Coffee makers of most types typically boil their own water (yes there are pourovers and chemexes, but they aren't that common and people who use them do buy kettles).

Nobody would buy a kettle for just cooking even if we did have more power delivery, simply because you don't cook anything by boiling all that often. Case in point: my family drinks tea, and so we own a kettle, but tea is really the only time we boil water (in the kettle or otherwise) for anything on a daily basis.