The established banks and the fintechs are eyeing each other up. Each side has what the other side wants.  The banks want the fintechs’ technology. Their IT is old and not fit for purpose. Their IT makes for fiddly apps, and makes it hard for the banks to make money from their users. Ancient IT is a big part of why banks can’t turn an economic profit. And it’s a big part of why their customers are flocking to slick fintechs like Revolut — which has mushroomed to more than one million users in Ireland. If the fintechs have the…