I'm seeing banks as not completely dying once bitcoin gains traction over mainstream media but wiuld take measures to integrate themselves to the new world. Like what the OP stated, they can set a buy crypto with us now, pay it later scheme to help investors jumpstart or boost their portfolios while still keeping their commerce alive. They wouldn't be easy to go down especially if we consider the fact that most banks have been here before our grandmas were born. Not that it's a good thing, but not a bad thing either. So unless we create or discover a complete replacement for banks, this is what I assume will be the case for the years to come.