To me, Jane Austen is arguably the inventor of the modern novel. Before there were fictional stories and books to read for leisure time enjoyment, people corresponded regularly by letters, and those missives were a form of entertainment, to be read aloud to one's family and friends (think of Jane Fairfax's letters to her aunt and grandmother (Miss and Mrs. Bates, then shared with the entirety of Highbury society.) Sense and Sensibility and Lady Susan were first written as epistolary novels, which was common as people switched from reading letters meant to entertain, to novels written using letters, to novels simply telling a story without the artifice of the letters. That Jane Austen managed to make that changeover pretty much seamlessly, shows how groundbreaking she truly was.
She was obviously clever, because writing a novel is something that takes more than mere ability. To quote Miss Bingley - There must be something more - ".. a certain something in her air and manner of walking, the tone of her voice, her address and expressions..."
Finally, she was ambitious. She wanted to be a successful author - to earn money which would have been so welcome in her family once her father had died. Her brother helped, of course, by providing Chawton as an abode for his sisters, his mother and family friend, Martha Lloyd, but without much income, the Chawton Cottage household struggled to get by. Wanting to provide a softer landing for her sister, her mother and her friend, as well as herself shows her ambition was a virtue.