They don't make them like this anymore (really)
I know it's a cliche, but just because it's used alot doesn't make it a false statement.
Nothing about this movie would fly with moviemakers of today. A downer of an ending,a cynical downer of an ending, unsympathetic characters (to include the good guys), criminals who have no redeeming qualitites and an overall feel of bleakness and decay. Wow.
The novel was written by a former prosecutor who was very familiar with the "Justice System" and the criminal culture. It's very obvious. I've been a cop for over ten years now and there isn't a false moment in the movie. It might be thirty-eight years old, but nothing has changed.
Oh sure the technology is different, clothing and hair, even the fact that semi-auto handguns have become more popular than revolvers, but that's all superficial. All in all that's the world of the professional criminal and the cop/Federal agents who pursue them. An outstanding example of the Seventies Movie.
Not real glamerous. Great movie however.