These are some of the reasons I've seen for why:
-the regulation isn't sufficiently flexible to allow the company to build it in a way that makes the most sense for their system
-for the same reason testing, user research and feedback largely don't matter
-the projects are led by legal or compliance teams who are generally terrible at building features
-the feature isn't requested by customers so the company has very limited dialogue with the user about it
-the feature will not make money so no one at the company is incentivized to build it well or spend time on it