Medicare was created in 1965 when people over 65 found it virtually impossible to get private health insurance coverage. Medicare has made access to health care a universal right for Americans once they reach age 65. This has helped improve the health and longevity of older Americans.
However, the program was created during an era when the big financial worry was that an illness might put someone in the hospital and generate huge bills. This was a period before the widespread use of prescription drugs to combat illness. The basic design of the Medicare program was modeled on the private insurance system in place in the 1960s. As the health care system has changed, many would argue that Medicare's benefits have not kept pace.
For more on the history of Medicare, see:
The official Medicare website is www.medicare.gov.