Your idea has been tried. You are describing MintChip, Canada's virtual money. Ever heard of it? ... exactly. 
How Bitcoin transitions to a government coin is entirely different.
That is different. However any change in the protocol would mean a fork. At that point it would no longer be bitcoin. It would also not likely be adopted. Are you willing to burn up your home wiring to generate money for the federal reserve?
Also what would keep China from then creating the lion share of the coins and charging Americans a premium. If it is not open source and beyond manipulation, then it has zero appeal.
You haven't really thought this through.