As to Ann Rice's success. . .
Well, INTERVIEW WITH THE VAMPIRE hit the shelves at the right time, and was reasonably well-written, boasted intriguing characters, vivid descriptions of New Orleans and a subtle subtext.
The next two of her "Vampire Chronicles" continued in that vein.
Those first three novels are a remarkable achievement as well as being highly entertaining reads.
Her non-supernatural novels, FEAST OF ALL SAINTS and CRY TO HEAVEN are also very fine reads. The latter is about European castrati and is rich Baroque-ism at its peak.
The Mayfair Witches novels failed to ignite a spark in me, I don't even think I made it through the first one.
I've not tried her erotica.
But, her "Vampire Chronicles" even fell apart for me around the fifth or sixth entry. Actually, it was the fifth: MEMNOCH THE DEVIL, which I barely made it half-way through.
Now, Rice has taken on the life of Christ, twice. . and, I have no interest whatsoever.
But, those first three novels featuring Lestat. . .ah, those are wonderful creations.