A constant surprise, to me at least, is the automatic assumption that come the global collapse a flood of currency will come into the market. From your average teacher to your average plumber, wages have stagnated and the cost of living has increased. To this extent in the event of a global collapse or even recession it would be lucky to even be able to put food on the table. 
With this wage stagnation and increase in living expenses, the average American not only faces a dilemma for survival, but in a crisis may face the dollar becoming increasingly devalued. With this in mind, expecting an influx of cash immediately into cryptocurrency might be too optimistic or even foolhardy.
A more relevant question instead might as well be "How long will it take for the populace to jump onto the bandwagon?".
As everyone on this site knows already, Cryptocurrency has many potential uses which are expanded upon seemingly every day. With these innovations in the cryptocurrency sphere one would assume people would jump in headfirst for fear missing out on this amazing technology, yet it will take a shock to ignite a movement. Luckily, the first step is already taken-- the populace is aware that it exists. Not yet familiar, sure, yet aware. Oftentimes, us, with the knowledge of the potential of blockchain, will forget that it isn't simply a currency, but an entire movement. A movement to bypass the banks and return to an era liberated from the corporate chains that plague us. In the end, the question will not be "Why Cryptocurrency", but "How did it take so long?".
-A Hopeful Skeptic.