Under M4A, the influx of new patients into the healthcare system could overwhelm providers, resulting in longer wait times for appointments, surgeries, and procedures. Countries with universal healthcare, like Canada, have experienced issues with wait times for certain procedures. A 2022 poll also shows that Canadians are less satisfied with their access to healthcare than Americans.

Doctors and specialists might lose the financial incentive to provide high-quality care if their earnings are capped under a government-run system. This could result in lower motivation, decreased innovation, and a drop in the quality of care and innovation in the healthcare sector.