The government can only stop the exchange between bitcoin and fiat, they can not stop the bitcoin network, thus bitcoin can not be stopped
That will stop any business from accepting bitcoin. But in my view government will only impose more regulations on exchanges to stop scams and black money laundering.
The ultimate goal of diehard bitcoin visionaries is for bitcoin to completely replace fiat. In this scenario there would be no conversion to fiat. Think about what could theoretically happen if governments banned the exchange between bitcoin and fiat but allowed businesses and individuals to accept bitcoin for sale of goods and services rendered.