If I were king, I would make a Law requiring all DVD & Blu-Ray distributors to include the trailer for the featured movie.
In other words, if I buy CASABLANCA on Blu-Ray, then in addition to the movie, director’s commentary, and anything else it might have – the disc must also have the coming attractions for CASABLANCA.
Why? Because the trailer has but one purpose: GETTING PEOPLE IN THE MOOD!
Suppose my wife wants to see the new french indie film Michele, Michele. Let us further suppose I have no interest in seeing it. If I watch just 20 seconds of the trailer, I will crave Michele, Michele as if it was the next Star Wars.
In this way, trailers are the “pushers” of the undesired movie. Regardless of whether the movie is good or bad, the trailer reliably hooks me every time.