Getting a mortgage through a mobile phone was once thought to be the final frontier. But Quicken Loan's Rocket Mortgage took consumers there at warp speed.

The Detroit-based company's literature brags that its platform allows users to complete a mortgage application without ever speaking to a human being – reflecting a culture and business model that is foreign to many credit unions. And cooperatives may only dream of airing television ads during the Super Bowl, but that high level of ad spending is nonbank lenders' oxygen.

Credit unions have been slowly gaining share in the mortgage market since the Great Recession, largely because banks stepped back their efforts. Meanwhile, the biggest advances have been made by nonbank lenders that leverage technology and advertising.