That makes a lot of sense, especially when you know that Inland Empire is a relatively poor area in Los Angeles where unemployment and crime are much higher than the average, and given Lynch's penchant for showing the hidden dark aspects underneath everyday life (Blue Velvet, Twin Peaks) or Hollywood glamour (Mulholland Drive), I wouldn't be surprised if he chose this title with the same idea in mind: in the middle of glamorous, star-studded L.A. you have this neighborhood where the people that didn't make it end up.
Also, Lynch himself announced the movie as being about "a woman in trouble". Most people take this woman to be Laura Dern's character(s), but I agree that it's more likely the Polish woman in the hotel room. I do believe, however, that The Phantom is real and not a figment of her imagination or some kind of metaphor.