Bitcoin can't be banned however, the government can ban it on their country because we saw some of the countries already that have banned Bitcoin to be used in their country but even though they banned it users always find their way to use it like using VPN's etc. Fortunately, there are more supporters of Bitcoin than not supporters. As a famous quote said "If you can't beat them, join them" so instead of banning it, they just supported it.
The more they put restrictions, the more people get curious about it, as many countries already said they were alarmed in popularity of bitcoin but they can't stop it's spread in their countries as many investors were smart enough to see it's ability to increase in future. Technology have created ways to create systems that will put there limits no use like in China even they ban exchanges, many chinese were still able to use exchanges every now and then thru VPN, going in other countries etc.