Bitcoin is really not in competition with the US dollar, it's in competition with gold, real estate, equities and other things that require armies to secure and enforce legal codes in order to keep them functional. Investment requires property rights and so people need property rights to make investments to free themselves from simple hand to mouth work or sustenance.
Bitcoin is property rights enforcement without property rights enforcers. Bitcoin is a way of extending the United States' long term goal of a globalized capitalist exchange driven dependence upon all from all, more effectively.
The US dollar is not the problem in this context, the problem is property rights enforcement currently requires violence and so liberating people is costly, bloody. Bitcoin doesn't cost blood to liberate the consumers of the still 3rd world oppressed, without strong property rights, the best weapon for this is Bitcoin.... at least that's the theory as far as I understand it.