The research fixates on the notion of "error/mistake" (because it's more easily quantifiable), but the reality is that most people do not get "optimal" care. In fact, in any given service, in any given industry, no one gets "optimal" care - that's just human nature. Doctors are humans.

It's also completely inefficient. Humans make judgement calls based on available resources. If everyone over 45 received "optimal" care, they would all effectively live in hospitals.