Re: Graphene
Nuclear fusion is only about 8 minutes away.
Carbon fiber is widely used, and has penetrated various markets at rates that seem plausible to me, given basic economics. I don't see how that example supports your premise, particularly in areas such as home construction, which tend to be very conservative and largely driven by regulation. We've had concrete homes, rammed-earth homes, Earthships, steel-framed conventional homes, manufactured-and-assembled-on-site homes, etc for decades, but on-site stick framing is still dominant here in the US. Why? Economies of scale, for materials and for expertise; and familiarity.
Biting the hand that feeds IT
