Many are dying without recovery because many sick people are not treated. That's because hundreds of millions of very young and elderly live in remote areas not easily serviced by doctors. Medicines sent to these areas are stolen and sold on the black market.
Another reason is that many diseases are mutating and no cure has been found yet. Consider also that global migration is rampant right now. Millions of people are crossing illegally into countries without being checked for diseases thus infecting countless other people. The dreaded ebola virus, confined to Africa, was recently found in Florida.
There are millions of people who do not have enough food. They subsist on foul drinking water, biscuits, and a handful of rice. The result is that their immune systems are not able to combat diseases like malaria, dysentery, and even plague.
Unfortunately, nothing is free. The medicines and bandages have to be manufactured, distributed, and then administered by trained doctors. If nobody pays for these things then eventually the hospital cannot buy more and sick people have to be turned away.