It shows how complex building a Fintech in US actually is , often due to how many different partners you will actually need to depend on.
In this specific case , you would need to have each partners offer an API that you could call to automate the mortgage workflow.
Obviously , due to the nature of the financial sector it's very likely those partners don't have those APIs and don't want to build them because they are sitting on a very profitable business and have no plan to change that anytime soon.
I can draw a comparison to Airbnb , where most of their jobs wasn't so much to build "disruptive tech" but to lobby local administration to let people rent their appartement to individuals , while hotel industry was lobbying the other way around.
It becomes even more complex when you realize you'll have to do this at global scale to build a unicorn.