Thereby perpetuating the illusion of stability - which might all be that's needed to continue with more people adopting it.
Bitcoin may be more vulnerable to these crashes than other currencies, commodities, stocks, or similar instruments. It's got a smaller size, lower volume, generally high volatility, and no sophisticated market instruments or automated high-frequency trading algorithms operate to make the market more efficient.
(oblig. disclaimer. this post is not a bitcoin advocacy post or a bitcoin hate post, but rather is meant to explore interesting properties of markets.)
There is no grantee of that with something as volatile as bitcoin. All it takes is the people playing the market getting burned one to many times and saying fuck it. This could happen tomorrow or never.
I really can't think of any investment as risky as bitcoin.
Oh, that's easy. Short-sell some overpriced darling stock like Tesla Motors or Amazon or something and watch the market remain irrational longer than you remain solvent. :)