All a bank is, is a UX on top of low-level financial APIs like ACH. If the bank then exposed an API, you could just use it to build another bank (without all the effort the original bank went through) and so compete with them on lower margins (because you don't have nearly the capital costs to recover that they do.)
Basically, it's the same reason that phone companies would never have allowed MVNOs to exist without legal regulation forcing them. The MVNOs outcompete the infrastructure-building phone companies, because MVNOs don't have to build infrastructure!
Comments
All a bank is, is a UX on top of low-level financial APIs like ACH. If the bank then exposed an API, you could just use it to build another bank (without all the effort the original bank went through) and so compete with them on lower margins (because you don't have nearly the capital costs to recover that they do.)
Basically, it's the same reason that phone companies would never have allowed MVNOs to exist without legal regulation forcing them. The MVNOs outcompete the infrastructure-building phone companies, because MVNOs don't have to build infrastructure!