Think about what it costs for an organization to adapt to a new set of regulations. A boatload of new paperwork needs to be setup, ordered, printed and distributed, after a thorough analysis of the regulations and a whole long process to determine documentary requirements. If software or electronic records are used, those need to be updated. The new set of rules need to be communicated to a large number of participating health care providers with appropriate document and/or software updates. Each of those things needs to be audited and certified. Personnel have to be trained to understand and comply to the new set of regulations and potentially certified. There would be a period of enforcement where nobody will quite understand the limits and those limits would be tested and the legal system would then clarify those regulations.
And that is just the tip of the iceberg. In such cases the massive one-shot refactor gives you way more bang for the buck than not.