For some people (not sure how many) there is just a small barrier to downloading movies illegally. You have to dip just below the 'honesty' layer and search for links in slightly questionable places. There's that feeling of being subversive and opening up yourself to a little risk (however minimal). This barrier can be just big enough in order to prefer things like Redbox or Netflix over it, but not big enough to make people go back to spending $5 to watch a movie at home.