I'm very curious about that.
If everyone decided that 1 BTC was worth $1.3 USD, then yes, the exchange rate would be just that.
However, not everyone is going to decide that. People who want Bitcoins are not going to pay $1.30 (or sell $1.30 worth of merchandise) for them because they are not confident that other people will, in turn, give them $1.30 worth of goods/services for that Bitcoin they just bought.
The reason, simplistically, is that there are too many bitcoins compared with too few goods/services being sold for Bitcoins. The amount of goods and services being sold for Bitcoins would have to greatly increase in order to bring people's expectations closer to $1.3/BTC