According to the CDC:
Severe complications in children and adults:
Some people may suffer from severe complications, such as pneumonia (infection of the lungs) and encephalitis (swelling of the brain). They may need to be hospitalized and could die.
Hospitalization. About 1 in 5 unvaccinated people in the U.S. who get measles is hospitalized.
Pneumonia. As many as 1 out of every 20 children with measles gets pneumonia, the most common cause of death from measles in young children.
Encephalitis. About 1 child out of every 1,000 who get measles will develop encephalitis (swelling of the brain). This can lead to convulsions and leave the child deaf or with intellectual disability.
Death. Nearly 1 to 3 of every 1,000 children who become infected with measles will die from respiratory and neurologic complications.
Complications during pregnancy. If you are pregnant and have not had the MMR vaccine, measles may cause birth prematurely, or have a low-birth-weight baby.
Long-term complications
Subacute sclerosing panencephalitis (SSPE) is a very rare, but fatal disease of the central nervous system. It results from a measles virus infection acquired earlier in life.
About SSPE
SSPE generally develops 7 to 10 years after a person has measles, even though the person seems to have fully recovered from the illness.
Since measles was eliminated in 2000, SSPE is rarely reported in the United States.
Among people who contracted measles during the resurgence in the United States in 1989 to 1991, 7 to 11 out of every 100,000 were estimated to be at risk for developing SSPE.
The risk of developing SSPE may be higher for a person who gets measles before they are 2 years of age.
https://www.cdc.gov/measles/signs-symptoms/?CDC_AAref_Val=https://www.cdc.gov/measles/symptoms/complications.html
My mother had measles as a child and described being confined to her bedroom in the dark, unable to read or have a light on because of the risk of blindness. Worse, her younger brother was just a toddler, and my grandmother had to keep the bedroom door locked for fear he would visit his sister and catch measles himself. She also had to literally boil my mother's sheets and pyjamas to keep the disease from spreading.
Just because nobody has died of measles in the last 6 years doesn't mean people won't die of it in the future (and 6 years is an extremely short time frame). Measles may be considered eliminated in the U.S., but the realities of airplane travel means the disease can strike from other countries.