That's a very valid observation and one of the reasons that bitcoin will accumulate real value as money reserve over time. It will start its mass adoption as an 'intermediate currency', until people get fed up with exorbitant fees and just leave their money as bitcoins. People will understand that there is an inherent trade off between trust and volatility in bitcoin, which is a positive thing.

Eventhough companies like coinbase are well positioned to profit from exchange rates, bitcoin is poised to generate much more value than that.