I've heard some fascinating stuff about passive airflow architecture. The floor plans of old buildings were often laid out in very specific and sophisticated arrangements designed to take advantage of local prevailing winds and weather patterns so that opening certain pairs of windows at certain times of day would effectively ventilate the entire structure. It's interesting to also think of the secondary effects we've lost by effectively sealing out the outside world and living in a closed box.
I would love to read a book on this: How far can you get relying purely on design and structure, not technology. "Passive" solutions, as you say. A fascinating topic.
100% is very feasible, even without going the Earthship route. Mostly it has to do with extra insulation but there are a couple other techniques that help. The reason more houses aren't like this is because it adds $10-20k to construction costs so developers don't bother.
