>Beyond the most hardcore users, skepticism has only increased. Nobel Prize-winning economist Paul Krugman wrote that the currency’s tendency to fluctuate has encouraged hoarding. Stefan Brands, a former ecash consultant and digital currency pioneer, calls bitcoin “clever” and is loath to bash it but believes it’s fundamentally structured like “a pyramid scheme” that rewards early adopters.

They were correct on both counts. Since then, proponents have simply stopped trying to sell it as a currency (buy your games in bitcoin! pay your rent in bitcoin! -- that was the initial pitch), and its pyramid scheme structure has only been exploited, not fixed.

[1] https://99bitcoins.com/the-rise-and-fall-of-bitcoin/