Oh no; you mean the existence of pesos, rubles and yen mean "currency" (aka the dollar) can be hyperinflated in substance?
Oh, and did I mention, my grocer doesn't take any of those alt-currencies; not even the euro!! Gotta be some kind of conspiracy.
Silliness aside, if nobody accepts those currencies as tender, they don't work. Nobody wants to use 100 different altcoins. We're all going to default to a few, and since this is the Internet, we're literally ALL going to default to a few--not just Americans all defaulting to the dollar, not just all Japs defaulting to the yen, but anyone and everyone coming together and using the same ones.
OTOH, once a dev releases wallet software which can safely store all the coins in one app, and displays the rates at which each coin translate into how much they're worth in Bitcoin, then we can use pretty much any coin we personally prefer. I can use Bitcoin, Litecoin, Terracoin, Peepeecoin, all conveniently located in the same (secure) wallet. That is, as long as a coin is popular enough to have market data