Looking at the price of an individual coin is a silly way to look at things. Look at the overall market capitalisation vs bitcoin and you will see the room for growth.
That would be true if they were direct competitors like Litecoin. They are not. They work together. However, Mastercoin will carry far more functionality than bitcoin. Mastercoin will finally far exceed bitcoin in value. Although bitcoin will always operate as the 'currency' portion of the system. Mastercoin will serve other parts = many other parts.
The protocols are not competitors but the coin parts of the bitcoin and mastercoin could easily be. BUT, that still doesn't matter too much, just think of what bitcoin can do, what value it has been given by the market for its abilities, think of what mastercoin can do that bitcoin can't and think of what value it could have if bitcoin already has a market cap of $12b.
Basically, what value does a protocol that offers trustless transactions of smart property, currencies, betting, issuance of shares and dividends, etc have if a virtual currency has a market cap of $12b?