Her contribution, such as it was, was to offer an attractive-sounding, if simplistic, defense of capitalism.
Unfortunately, her vision of heroic individualist industrialists does not address the sort of corporate conglomerates we see all around us today. The individual moral rules she embodied in her characters does not translate well into a huge multi-national corporate environment.
As an economist, she was a pretty ham-fisted novelist.
In terms of her influence, I think the most telling example is the man whom she excommunicated from her circle of disciples: Alan Greenspan.
I believe he defended her during the split of the group. Also, he invited her to Ford's inauguration and he attended her funeral.
She had an influence upon rank-and-file millions through her book and the movie, "The Fountainhead".
I feel she was a little loopy, but do appreciate her efforts against socialistic trends in the 50's.