I wouldn't worry about the 538 map yet. Trump got a bump in numbers from the messy end to the email scandal, and from his convention happening. Hillary's numbers will rebound, just like Obama's did in 2008 and 2012, to a bigger lead by the actual election.
Honestly I never liked the "break up the banks!" rhetoric anyway when said breaking up wouldn't really resolve the core issues.
The issue wasn't breaking up the big banks. A lot of smaller banks don't have the rules the big ones do when it comes to ripping off individuals. He also refused to sign a letter calling for a new law to stop payday loan abuses.