i'm not convinced the currency can survive since it's really blind faith that is holding it up, so i'm partially just examining an end-game scenario.
If BTC starts to plummet (which will likely happen at some point in an ecosystem so volatile) people may literally lose their investment entirely. Why? No one will want to sell assets they paid $600 for for $10, they'd rather believe it is going to climb back up. Then even if they decide "fuckit it's over its just a currency now I guess I'll sell" nobody will want to buy. They'll instead buy a cryptocurrency that has a better theoretical mechanism for stability and can actually be used in practice (unless people are so dense that they want to restart the speculation cycle).
The ecosystem could just freeze and there is no way to force people to continue to buy into it (I once read an analysis by an economist in which he mentioned that black marketers may end up having to intimidate constituents to buy into it in order to keep it afloat).
Basically this all kindof boils down to a Game Theory issue where everyone wants to sneak their money out at the proper time in order to maximize their cashout before the system fails or the market corrects (I'm not sure it ever will based on the nonsense principles used to design the mining rules / currency cap).
But not everyone can cashout at the amount they paid in. In fact, as I point out in my endgame scenario, many may not even be able to cash out at all. It's a mass vehicle for redistributing wealth and the volatility makes it useless as a currency. It may take a while to fail but when it does a lot of people will get screwed.
Think about it. The guys with those hoards are probably slowly cashing out 10 BTC now & then to put 5k in the bank, knowing full well that these crazy prices can't hold forever. They are a godsend for the scheme's designers who printed all the free money for themselves. For blackmarketers & gambling sites its more dangerous because they may end up with a wallet full of worthless coins.
When people say "Don't invest more than you can afford to lose" I like to internally translate that to "Don't invest more than you'd be comfortable with having a criminal potentially steal from you".
And then good luck trying to get the US Gov to bail you out, lol. They are looking at Bitcoin totally amorally to understand it. They couldn't give a rats ass about the investors. Amway is legal, after all. :D