Yeah--that was the whole point.
As for it not saying anything new about the subject, I must have missed all those dozens of movies that depict drug addiction in aging women with no lives. I've never seen the horrors of addictions depicted so believably.
If you have a list of all these other movies about the same subject, I'm all eyes.
BTW, being faithful to the source material is a good thing. I prefered the movie's actual depiction of the situations to the book, which was even worse than Last Exit to Brooklyn.