I don't think many bitcoin users want their currency to become main. As for sure, we can't even dream about it for next nearest 10 years.
I believe that it is proper for bitcoins to be not a main currency. If it becomes a main currency then its value will no longer rise. The increase in value is one thing that makes this coin very special as a currency. If it becomes an ordinary currency then there is no much fun in it and we will no longer enjoy the price increase when the time comes.