That's odd. I've been here since 2010. I've seen soo many cryptocurrency bubbles burst over that time and it never took 2 years to start recovering. I mean sure maybe this time it's different. Of course it COULD be different this time. But you say this like its an established pattern.
*edit* looks like it took almost 2 years starting in 2014
Late 2013 bubble bear market lasted 14 months. From start of December 2013 to end of January 2014. That bear market was longest because year 2013 had two bubbles.