If it's at all possible for anyone to be more greedy than MLB, it would have to be RIAA. FM and AM don't have to pay royalties, why should XM?
Anyway, both Sirius and XM are losing their shirts, trying to woo subscribers to get to a critical mass where they can eke out a profit. If you diverted 30% of an already inadequate revenue stream, that would be the death of satellite radio.
Notice they are not worried about people recorded FM any more, cause for the most part, there's nothing worth recording.