The lack of demand of the dollar by other countries looks more of a threat to the dominance of the dollar as reserve currency and that is why the likes of China, Russia, Brazil, South Africa are looking towards using other currencies for internation trade. Also the stacking of Gold by most of the countries even Saudi Arabia has signifies that most of these countries are moving towards storing their reserves with currencies or commodities of value.
Aside Gold the biggest threat I see to dollars is the bitcoin. The gold isn’t just gotten or accumulated by a common but since it doesn’t comes in fractions like that but with bitcoin also acting as a store of value and can easily be bought in fractions (satoshis) then investors of dollars might start moving in flocks to bitcoin just to save there funds from depreciating.
So it’s going to a tough time for dollars considering how Russia and China are up against it. It won’t be upsurge easily like that as a international exchange currency but it will be faced serious challenges