A very well-known DVD producer, who has always gone the extra mile to license original music when releasing DVDs, once told me that the rights holders to most music are like real-estate investors. They buy and sell these songs for the express purpose of making money off of companies like the DVD...
The rub is that if this release sells well--or, at least, no differently than the previous seasons--CTHE will have little incentive to continue paying music rights for other releases.