Upper-class?

Some posters have suggested that Lewis and Elizabeth are upper-class. Do not be fooled, for there is nothing in the least upper-class about the couple. They are merely rich, on account of his trashy fiction, and vulgar with it. The fact that they live in such a false bubble, derived from peddling lies, fuels their separate and joint ennui.

Isn't the film asking us whether they are any better than the drug courier and gigolo Thomas? Isn't the end depressing: that it's back to the old treadmill, stuck with each other?