For all the perma-bears out there, Bitcoin is just another example of how difficult it is to detect so-called "asset bubbles" in real time.
I remember Tyler Cowen, among many others, calling this a bubble when the price was just $30 back in 2011 (bottom chart)!
Oops! That's almost as embarrassing as Jeremy Grantham's peak oil prediction back in 2011. Unfortunately for Grantham, he also predicted Australia's "housing bubble" would collapse about 10 years ago. Another big oops. He appears to have predicted 10 of the past 3 bubbles. And poor old John Hussmann who has been calling for the next stock market collapse since 2008.
However, I should note that we all dabble in amateur forecasting. I've been guilty of that myself, not least in relation to the Chinese economy. Every man and his dog expects China's economy to follow the path of Japan in the 1990s. The problem is that, when everyone sees the same thing, it tends not to happen.