It's almost like growing up during a major financial crisis that wreaked economic havoc all over the world has caused young people to look at banks with suspicion! Years ago, bank managers often knew their customers. Nowadays, they never see them. To be fair to both millennials and banks, this probably has more to do with technology than anything else.
If you go back a couple of generations, anyone wanting to withdraw money from a bank had to go inside to do it. Now, ATMs make that unnecessary. On top of that, most banking products are now applied for online instead of in-store, rendering many physical banks obsolete. If your customers can do everything online, they have no need to come and see you in the flesh. 40% of people under the age of 24 say they have never set foot in a physical bank at all.