to me as US Dollar is the most popular currency of the world and is also the most stable, as it dominate all the other paper currencies of the world, so we can say that it also dominate the bitcoin, but i think there is no match of USD with bitcoin because USD is a paper money where as bitcoin is a crypto currency.
The US dollar is the most stable or the stongest currency now. It might be replaced by the bitcoin in 20 years.
It will never be happen that usd can be replace by bitcoins .. bitcoin will always just use as alternative payment processor online we can not change that.. only the adoption we will see for bitcoin and price increase .. and more people using bitcoin..