HunchBluntley: Alan Wake was pulled from sale at least in part because it incorporated licensed music whose limited license ran out.
GTA: San Andreas had a number of songs pulled from its in-game soundtrack for the same reason (even for people who had purchased the game well before the licenses expired).
Mafia II went away for a while, only to come back with a butchered soundtrack. And so on.
OP is worried the same will happen with
Fallout 3. It's a valid worry. (Though I don't know how famous any of its licensed music was when Bethesda first licensed it, so they might have been able to afford to license it for a much longer period. Or they could probably afford to just pay to extend the license, given how profitable the series has presumably been for them.)
hedwards: Knowing Bethesda, I doubt they paid much for the licenses.
Also, at this point, I doubt anybody really wants to hear those songs ever again. It's a rather long game and the number of songs is pretty limited. You'll hear each song probably a few dozen times before being done with the game.
I'd rather see them remove the money and replace it with something that's free or extremely cheap.
If the radio in Fallout 3 is too limited for you... -