I'm in agreement with Jallen. All great art is subject to multiple interpretations. That does not necessarily mean one has to like it. Yet, it can be quite provocative - as is this film.
I live under the H of the Hollywood sign. I work in the film business as a Director of Photography on features and television shows. Mulholland Drive reminded me of a book called "Day of the Locust" by Nathaniel West (I never saw the movie). As you may know, Nathaniel West was a successful novelist, around the 1930's, who was lured to Hollywood by the studios - meaning big money - to write scripts. Yet, he fell into the same trap as F.Scott Fitzgerald. The business of Hollywood is unspeakably nasty. It respects no one. One is never sure who they can trust. To endure it, takes enormous survival skills. I'm not sure if anyone survives this town unscathed. The expression,"Hollywood Blvd.- street of broken dreams" is all too true. Anyway, Nathaniel West wrote "Day of the Locust" as a twisted fictional tribute to this twisted business and how it affects the innocents and not so innocents.
Mulholland Drive, to me, seems to mirror the surreality this actress has acquired after arriving in this town as an ingenue'. After winning the dance contest back home, she was ready to become a star. The couple that she net at the airport at the beginning of the movie - had Cassandra type grins of knowing what this innocent was about to undergo. Stardom was not to be hers.
So, I do think that this film has a great deal of 'inside Hollywood' stuff, yet, I also believe that it works quite well as an abstract mystery. Some of you
may know that this film was originally intended to be a pilot for a television series - a la "Twin Peaks". The networks rejected it so David Lynch reworked the script and shot additional footage to make it into a feature.