Just think about how much of the country doesn't have HAA coverage (or enough per capita) and the world gets along just fine.
HAA is a nice to have, not a need to have. It's typically unfair to society in how it's currently managed in the US.
My experience was that 10-15% of flights were needed scene calls and 20-30% were necessary hospital transfers. For the rest, an ambulance would have been just fine for the patient; no need for highly trained med personnel and no critical need for speed. Just saddling people up with huge and unnecessary medical bills.
Granted, my experience was at a community base around class B and class C airspace (for city size comparison). Typically 20 min to scene, 20 min to hospital, 20 min home. I would imagine the percentage would be slightly better for more rural bases.