Every little piece of a movie or TV tie-in costs extra. Back when I worked on NES games, for the Terminator movie license, all [my employer] had rights to was the title, the title logo, and rights to imitate the scenes and robots in the movie. The terminator could NOT look like Schwarzneger. They didn't have the rights to "his likeness" or his voice. It would cost too much to get those rights.
Same goes for sound samples. Each one has to be licensed and paid for.