No I do not think that banks can be destroyed by the bitcoin itself, the government will indeed stop this and the banks itself also has enough power to stop this easily.
i think no one can stop bitcoin not the governments and nor the banks, banks and governments have to admire the importance of bitcoin and they have to accept bitcoin as legal currency. the banks will also start accepting bitcoin in future.
Lol I think there is no necessity of government to legalize bitcoin, you can not intervene in the government to legalize bitcoin, because it is futile
but even so, I'm sure bitcoin will continue to grow
The legalization would be easy for them if they can control it, but bitcoin is not being controlled as it's decentralized so it's impossible.
What they can do is to require exchanges to regulate strict measures to comply with the basic governmental rules especially the anti money laundering act and to make sure every suspicious illegal transactions shall be reported. Overall, we can easily be trace as in the end we will convert bitcoin to fiat.