A lot (most? all?) of these "edge cases" end up handling regulatory or other forms of compliance, which came into effect after the initial software design. The

A lot (most? all?) of these "edge cases" end up handling regulatory or other forms of compliance, which came into effect after the initial software design. There might have been 10 people across as many teams who discussed, designed and vetted a one-line code change. It's not so easy to "simplify" out features which are legal requirements.