Reserve currency status entirely depends on whether the issuing authority has the ability to drop a munition (literally or figuratively) on the head of anyone who dares to counterfeit the currency.

China's military and soft influence are improving but until they get that good, USD will remain the reserve.

Because, imagine the scenario where the US simply counterfeits the renminbi. What is China's recourse? Spicy statements by Wang Yi in toothless international forums?