How and Why are bad movies made?

After years of witnessing and sitting through some very bad movies and seeing first hand the difficulty of writing a good or great screenplay and then getting an agent and then turning that miracle into an actual movie I have finally come to the realization that so many movies are made because of corruption in Hollywood. Friends making promises to other friends, favors paid in order to make some other movie or get some other script approved. Right now it seems that Seth Rogan and Adam Sandler have cornered the market on getting some very bad movies released and somehow bypassing the DVD and B movie path to go directly to the mainstream theaters. Some recent examples of this are the Interview, Pixels and most recently the Night Before.  These movies are so bad that anyone who read the screenplay would realize immediately that there is no way a movie this bad should see the light of day.  The worst part about this is that some very good movies or great movies will never be made because garbage like this is taking up all the time and money that could be devoted instead to a script that is worthwhile.  Hollywood is a business made up of favors and pay-offs and some very bad decisions that over time will degrade the quality of entertainment that gets put out into the mainstream movie theaters in this country. Too many of the wrong people are in charge of the decisions that are made that this is highly unfortunate for those of us who love to go to the movies and hope to see something that has some quality.