You have made a major point. There is a limit to how much good doctors can do when patients are unable to afford help.

However, there are some absolute basic things that go a long way in reducing mortalities just by encouraging people (especially the most financially challenged) to seek help.

For example, where I work currently, malaria testing and treatment is free of charge. Many patients don't know that!
Sometimes kind hearted investors have taken up a patient- and paid for the entire treatment.

However patients who never come would never have access to even the free things.

It is a fight that seems daunting. Victory seems impossible, to be honest. But we can start with the few things that are within our control.