The Medicare program was developed in 1965 as a health insurance program for people who are eligible for Social Security. Medicare primarily pays for acute care, things like doctor visits and hospital stays, but does pay a little bit of the cost of long term care. Up to 100 days of a nursing home stay may be covered by Medicare if the stay follows a hospital stay of three days or more and the purpose of the nursing home care is to rehabilitate the patient. Medical care delivered by a certified Home Health Agency might be covered for some period of time, too. Extended nursing home stays and 24-hour-a-day in-home nursing care are NOT covered by Medicare.
Also not covered is the cost of most prescription drugs, including most oral drugs taken at home by people with chronic medical conditions. There have been attempts to add prescription drug coverage to the Medicare program, but it's unlikely that the Medicare trust fund is large enough to add significant new benefits at the same time that millions of Baby Boomers become beneficiaries of the Medicare program, so Medicare is unlikely to become a payment source for any more long term care costs than are already provided.