Does anybody READ anymore?
Whatever your opinions are about this movie or PT Anderson, it's astounding that most people don't seem to appreciate that this movie is based on a recent novel by a man who is regarded as one of the great living American writers and whose previous novels have never been filmed and are all but un-filmable (some would say "Gravity's Rainbow" is also un-readable).
I'm glad most people at least know what film noir is. That's why this movie SEEMS a lot like "The Big Lebowski"--they were both influenced by film noir and the LA noir variant. But those were also based on BOOKS originally (which were called serie noir in France) like Raymond Chandler's "The Big Sleep", which has a confounding, labyrinthine plot that makes this movie seem relatively easy to follow.
If this movie (and the book its based on) was inspired very much by another movie, it is probably the Robert Altman's adaptation of Chandler's "The Long Goodbye", which updated the 1940's novel to an early 70's setting when that film was made. But the fact that this is a book of literary merit explains why it's too complicated for a lot of today's simple-minded movie audiences to grasp. But I think the problem is literature is allowed to be vague and ambiguous and tell things only from an oblique and limited point of view. A fly struggling in a spider's web is NOT going to appreciate the full design of the web, but a writer is allowed to tell the story from the fly's POV. Today's movie audiences though think they need to have every little thing explained to them.
My point is if Anderson had completely bastardized rather than (relatively) faithfully adapted the book, it would be a lot more popular with a lot of the illiterate nitwits bashing it on this page.