I do not think bitcoin can destroy the banks. People do not change their habits easily. They also trust the bank too much. If the bitcoin starts to be used by a few billion people around the world, the banking system could end up.
But the states will not allow it. States always support systems they can control.
in fact it is not possible in present time. because almost all the people of the world are using fiat and the user of bitcoin are still very low. i think in future when the users of bitcoin will increase then it may become possible that the use of banks will decrease.
Despite of the lack of support of the government on bitcoin, I still see that the users will continue to grow. However, I do not see that growth would be substantial enough to surpass the volume of users of the bank. Since fiat is the most popular money in this world, bitcoin would only live in the shadow of fiat.
it would just crazy when you have and use a currency that worth $1,000 USD

, common people not yet ready to accept that fact. we might have no problem at all with that condition , but still the bitcoin headaway far from established for now. one day this scenario might could happened i believe , just the matter of the time and noone knows.