This is one of the producer's jobs, yes. However, to clarify, there is more than one type of producer. The executive producer is the person who is either paying for and/or lining up money for a film to begin. However, there are also line producers who oversee physical production. There are development executives (sometimes also work as line producers) oversee the script development process. Then, there are the "producers." These guys are the wheelers and dealers. They get all of the preproduction going. They oversee it. They make sure everybody pulls their weight on set. And then, they also oversee post production, and then they are the ones who usually take over marketing for a film. What most people don't understand is that making the film is half the battle. Why make a film if nobody is going to show up for it? That's the job of the producer a lot of the time. Get butts in seats, people - to quote George Carlin.