We like to waste a lot, particularly, in the kitchen we like to wash the hot water down the tubes, literally, right into the sink. We even heat up much more water than we need: 2 leters of water to make a cup of tea or boil half of pan with just two eggs in it. We like to flush the boiling-hot water into the sink. Probably, that is the answer to my question, but I would like to ask it anyway: why do you like the cookware not to be thermally isolated from the environment?
I know some physics and chemistry to understand that, in order to cook something boiling, you need no more than to heat up the water to 100°C and leave the pan at that temperature. You should not waste more energy to maintain the temperature. It is the principle of Galileo, who taught us that you spend energy to speed up your car (raise water temperature), but, as soon as you reached your target speed (water is 100 degrees hot), you stop the acceleration. The cooking can proceed to completion, despite of zero energy inflow, because cooking is a flesh denaturation, which is driven by temperature rather than energy wasted. The only reason that you need to add some energy is the thermal leakage or friction. But, theoretically, if you reduce the thermal leakage to almost zero (nobody says that you cannot), you can cook anything for free as long as you like. Theoretically, you can even use heat pump to transfer the heat from ready cooked pan to a fresh one, exchange their temperatures and cook as many dishes as you wish with zero energy (waste).
This makes me to ask, why don't you like it? Many of you, if not most, prefer to cook without the lid (!) and nobody cares about thermal conductivity of the lid and walls, where you have the leakage even when pan is covered with lid.
I read in WP that thermal conductivity has a significant effect on the cookware items. What does that ever mean? I see that any pan is a 3D object, which means that it has 6 surfaces: top, bottom and 4 walls. Only one of 6 surfaces needs the thermal conductivity. Why don't you see that and make your cookware of homogeneous material? The energy that you supply from the bottom leaks from all other surfaces! The more conductive material you make, the higher is leakage. I would make the bottom highly thermal conductive whereas insulate the walls and the lid.
Currently, I have to drop a towel on top of the pan, but that is risky. I therefore would prefer to see the thermally-isolated cookware in the store. But you do not like it. Why? Why don't you want to travel the infinite distances at a finite drop of the energy?
It may be fine to leak the heat at winter but you do that all the year along, even during the hottest summer days. You use your cookware to heat up the rooms. I can guess that the answer is "it is irrelevant since losses are negligible contrasted with the bath/shower, for instance". But, please, confirm anyway.