Knives are not just weapons, and if you think forks can replace knives then you have never actually cooked anything more complicated than instant ramen. Go to your favorite restaurant's kitchen, and you will see lots of knives, specialized for various purposes. Knives are among the most useful tools ever invented. Quite a few people (myself included) carry a pocket knife or multitool (which almost always includes a knife) everywhere. There are a lot of situations in life that call for cutting things.
"I'll give you the wheel only because I'm still waiting for my hovercar"
Your hovercar will probably have wheels, unless you think there will be no need to cool any of those high-tech components (or that the cooling will be accomplished without any fans -- I doubt it). Even if we had a world of hovercars, there would be wheels all over the place, in various machines both in our homes and in factories and other industrial settings.
Fires are also better for everyday domestic cooking, whether due to basic usability (in the case of a hob) or warm-up time (in the case of a grill or oven).
Passing electricity through bits of metal until they heat up is fine, but I don't appear to be unique in my feeling that simply setting stuff aflame works better. So all in all, I don't see the humble fire going anywhere.
(Lest you think I'm a stick-in-the-mud, do note that I fully approve of the use of electric light over candles.)
Last I checked, my gas furnace was basically a controlled fire.
knives superseded by guns (weapons) and fork (cutlery).
I'll give you the wheel only because I'm still waiting for my hovercar