Lower cost = more sales
When I first got my Blu-Ray player retailers were charging in excess of £30 for some movies - I only brought 5 in 24 months. Over the past few months I've noticed lots of sales dropping the cost down to around £8 - £15 a disk, as a result I've now brought dozens, including duplicates of those I had on DVD.
Content producers really need to stop taking the proverbial if they want to maintain sales, hopefully these lower prices will become uniform.