Yeah, it's apparently possible to short bitcoins. If the recent rise in price is a bubble, and it crashes back to about $30, it will still come back to about $100 in a year, if bitcoin adoption continues.
If bitcoin will become a major currency, it will have to have a phase where it cannot be used in general and only with a small number of companies. That's not evidence that bitcoin will not become a major currency, it's evidence that it hasn't yet, and nobody claims it has.
So at this point it's really an investment vehicle and a convenient method of exchange, not a replacement for fiat currencies.