I'm not clear on what list you think Rand might be added to, but when I was an undergrad over 20 years ago, our philosophy department included a course that covered some of her work, among that of others. She was mentioned by name in the course description, though I can't speak to the content of the course beyond that.
In order to understand the problem of her popularity among philosophers compare her to someone else who was influential in having written philosophy, plays and fiction, and also for having had some political influence: Jean-Paul Sartre. Imagine Sartre's position in the canon if his writing was not Nobel-prize quality and was - let's be frank - pretty bad, but he was still in possession of some political influence, somehow, as a public intellectual. Under those analogous circumstances, I'm not sure we'd even know who he was here in the United States.
In order to understand the problem of her popularity among philosophers compare her to someone else who was influential in having written philosophy, plays and fiction, and also for having had some political influence: Jean-Paul Sartre. Imagine Sartre's position in the canon if his writing was not Nobel-prize quality and was - let's be frank - pretty bad, but he was still in possession of some political influence, somehow, as a public intellectual. Under those analogous circumstances, I'm not sure we'd even know who he was here in the United States.