By 2007, the globe had crossed a radical threshold: Half of us now lived in cities. - Peter Diamandis

In one of his later volumes, Earth, book XXXV, Pliny tells the story of a goldsmith who brought an unusual dinner plate to the court of Emperor Tiberius.

The plate was a stunner, made from a new metal, very light, shiny, almost as bright as silver. The goldsmith claimed he’d extracted it from plain clay, using a secret technique, the formula known only to himself and the gods. Tiberius, though, was a little concerned. The emperor was one of Rome’s great generals, a warmonger who conquered most of what is now Europe and amassed a fortune of gold and silver along the way. He was also a financial expert who knew the value of his treasure would seriously decline if people suddenly had access to a shiny new metal rarer than gold. “Therefore,” recounts Pliny, “instead of giving the goldsmith the regard expected, he ordered him to be beheaded.”

This shiny new metal was aluminum, and that beheading marked its loss to the world for nearly two millennia. It next reappeared during the early 1800s but was still rare enough to be considered the most valuable metal in the world. Napoléon III himself threw a banquet for the king of Siam where the honored guests were given aluminum utensils, while the others had to make do with gold.

scarcity is often contextual.

The day before something is truly a breakthrough, it's a crazy idea.

If you are risk averse and stick with safe, proven steps--then you're ultimately stuck with incremental progress, not breakthroughs.