Will banks fold if they don't adopt crypto currencies. I think as important and sensitive as this question is, I don't really thinks that banks will fold if they don't adopt crypto currencies because while bitcoins are digital and decentralized, banks deals with hard currencies like the united states' uses the USD in their Banks and so long as the USD is in use the banks will still operate, because they will be there to do the day to day transactions of the United States Of America. Though the activities can be reduced if Bitcoin is accepted beyond what it is now.
for now, trust in banks is still quite high, it can be seen from many people in banks or those who make transactions. Even so, many of today's young generation are interested in progress and fast services such as crypto and bitcoin, but banks themselves must survive with their abilities even though they do not adopt cryptocurrencies because each has its own path and from crypto innovation, it does adopt technology that has its own advantages.