I personally do not consider banks going extinct because of cryptocurrency. Mostly in my locality people didn't even care much about cryptocurrency and if they do it would only account to a few people because more are investing to get real money everyday on businesses that involves marketing of products which cryptocurrency might not be used for selling and buying due to possible loses out of volatility.
Yes you have a point, you are right that crypto maybe will not affect banks as banks are there for many years now even if cryptocurrency will be live and popular in the coming years.