bitcoin and because of it cryptocurrencies is a growing phenomenon that they can not do anything to prevent it. so if the government wants to keep their control over the market they would have to forget about a total ban of cryptocurrency exchanges and instead think about regulating them in a way that they can keep people on these exchanges and have control over them.
otherwise we have seen total bans leads to migration not prevention. people simply start using other methods of trading, methods that involve decentralization and remove government control altogether.