Earlier quoted context omitted.
Now do the Federal Reserve. 1955 Tappan Zee bridge: $55 million. 2013 Tappan Zee bridge: $4 billion for basically the same bridge. Due in part to the destruction of the USD caused by the Fed.
The reason the dollar is a currency is because of the existence of a force (in this case, the Fed) that can tamp down speculation and deflation. Cryptocurrency doesn't have this, and that is its central failing.
Speculation is a good thing, it's a form of entrepreneurship.
Example of historic deflation: https://en.m.wikipedia.org/wiki/The_Great_Deflation