Because an EHR is not just about collecting patient history and outcome. It often includes billing, accounting, and management. Then you have to consider multi

Because an EHR is not just about collecting patient history and outcome. It often includes billing, accounting, and management. Then you have to consider multiple decades of paper records, and records from other systems. Then there's many hospital systems composed of multiple health entities (hospitals, clinics, stand-alone emergency rooms). Some hospital systems span across multiple states and each state have their own set of rules (don't forget about the federal rules as well - HIPAA). Then when you are building out your EHR system. You have to take into consideration the aspect from the doctor. There are many specialties within medicine. An EHR record from the point of view of an emergency medicine doctor vs a radiologist is very different.