Dollar hegemony won't end because it cannot: no other currency bloc will allow the enormous trade deficits need to become a reserve currency, and the political risk with China vis a vis the yuan is so insanely high that no one would accept it as a long term reserve.
Germany's and China's exports would also tank-- right now the ECB is worried about a collapse in German exports driven by a rise in the Euro vs. the dollar.
Your comments are well-reasoned. Thanks.