It seems like newcomers aren't interested in PvP. Or to put it blatantly, the old SB culture is dead and the attitude of live-and-let-live is threatening to replace it. ...ummm... Is it really bad if people in SB no longer do PvP? If people can PvP somewhere else, is it really worth it to preserve the BG's?
Giving rewards as an extrinsic motivation to make them do what they don't want to do... I think it only work on kids. The way I see it, those BG rewards are the ones that doesn't help at all. Perhaps, it makes it worse by attracting the weak looters more than the PvP-capable players.