The price of those medications makes them available to a small portion of the people that need it.
I work at an agency that advocates for people with serious medical problems and I'm pretty familiar with the situation. These drugs
are criminally expensive, but are usually covered by health insurance and Medicaid. There are also programs like the Ryan White Foundation to get the medication free or at a greatly reduced cost to uninsured/low income people.
These drug programs also were mind boggling complex at first (10 to 20 pills a day) but now many involve only one or two pills a day.
Unfortunately there are people in the U.S. who don't have access to the drugs, and millions of people over the world who do without mainly because of cost.
South Park did a brilliant take on this recently when Cartman gets AIDS and the gang goes to visit Magic Johnson to see how he keeps so healthy. Turns out - the cure for AIDS is to have massive amounts of money!