Your "basic chemistry" doesn't match up with the lived experience of the plethora of people that frequently use cast iron/carbon steel. And yes, it doesn't matter what type of pan, including non-stick, if you want your food to taste good you're probably gonna start by heating up some fat. You're only building excess carbon in a cast iron/carbon steel if you leave on bits of burnt food and season over that. If you clean your pan properly (with soap and hot water, because that's totally allowed), that won't happen. Tons of people cook with cast iron/carbon steel every single day and have absolutely no problems with it. And don't get me wrong, I'm not saying everyone should only cook with cast iron/carbon steel, all I'm saying is using those pans is way less finicky than you're making it out to be.