Alas I have not seen the film version of American Psycho and so I can't comment on it. However your political take on it is very interesting, and an example of how time does things to movies and the way we interpret them and feel about them.
Films that were flopped or received tepid enthusiasm from viewers initially can be hailed as classics twenty years later, etc. Sept 11th certainly cast much of the 90s in a different light than was possible for us to see before. And films are a whole separate art form anyway.
Getting back to the written version of Psycho, I don't have a problem with the endless couture descriptions in and of itself. And audience fascination with the workings of the ruling class is certainly a time-honored tradition to which I also subscribe. In fact I enjoy it, so long as there is soul behind it. I actually am drawn to authors who give their readers a king-size bed of description regarding characters clothing choices, personal appearance, hairstyles, etc (one of my favorite books of all time is Scruples by Judith Krantz, a perfect example of Good Trash and a high-fashion bible to boot). But if there is no passion, then the work reads flat, dull, uninspiring and vacuous. Of course one could retort that the coldness and vacuousness is Miss Ellis's entire point, but I felt that point was already well struck in Less Than Zero. Perhaps American Psycho was his attempt at representing the more monstrous side of that vacuous scale, but whatever.
Granted as authors we are repeatedly drawn to portray the same themes and subjects over and over. Will Miss Leroy have anything else to talk about besides child abuse and prostitution, now that she's already run us into the ground with it in two novels? Time will tell. And granted also that versatility as an author is far less important than quality -- better to write five really great books about one subject or theme than to write five so-so books about totally divergent topics. Miss Leroy, at her young age, has already written Literature. I guess the difference between her and Miss Ellis is that the former's style triumphs over everything else. Not so with Miss Ellis.