The answer to your question is in your post. "She died a lonely old lady".
One of my grandmothers was never lonely. She became a vegetarian at 35. She got around and was well until she died in her sleep at 101.
My other grandmother had a stroke at about 80 (she wasn't a vegetarian) and didn't want to go on. She died 7 yrs later of a urinary infection.
After she was gone my grandfather was so lonely that all he kept saying was that he wanted to be with her. He had been a vegetarian all his life and was in good health.
He said he didn't feel well and went to the hospital. Then he told everyone he didn't plan on going home again.
All the family went to see him to say goodbye. He died of pneumonia that week at the age of 88.