The human body hasn't change much in the past 150,000 years.
Are there many new diseases other than AIDs?
How long does it take to understand the human body?
The quality of care wasn't bad 50 years ago. How much did it cost then?
Profit? Yeah- how much do drug companies spend every evening on adds in order to sell us a treatment for just a symptom of a disease?
Most of your "profits" come from the efforts to try to extend peoples lives for a few years.
If necessary save a buck, just let nature take it's course. Seriously.