So here's my theory - the reason Fridays went from "Mastertape Theater" to "Best of the Week" is because Stern is planning to sell Sirius the rights to play his old tapes after he retires next year. There's 10-20 years of tapes so Stern could keep getting paid for another 5 years at least without actually having to work. I think he stopped the use of the tapes every Friday once it occurred to him that he can make money off them.