"Why are your houses so heavy?"

Bucky Fuller

...was interested in portability and nomadism; while a concrete foundation with utility connections was necessary, Fuller's idea of moving house was that you could pack your house down into a container that would fit on a truck, drive it to your new neighbourhood, and deploy it again — the design influences of the traditional Mongolian yurt should be obvious. The Dymaxion House used aluminium sheeting for floors and structures, suspended by wires from a central steel structural shaft: saving weight was a priority. As he famously asked an architect on one occasion, "why are your houses so heavy?"

via Charles Stross

Not sure it makes much sense to compare Fuller's Dymaxion house with Brutalist architecture, as Charle suggests, very very little of which was ever used in detached housing. A better comparison would be the Dymaxion house versus the mobile home or, if you are looking at the traditional and still most effective way to build quality housing, then versus 2 x stick-built. I've developed pre-fab housing and I'll bet you that in 50 years we are still building site-built stick construction (for detached and low-rise attached housing.) I could go on at length but many people want to believe otherwise (e.g. that pre-fab is "greener") and so I'd waste my breath. Yes, I love Bucky Fuller but when it comes to sustainability, it doesn't matter "how much a house weighs."