@LokiLeo789 A Buster Call is intended to completely destroy everything within, like, a ten mile radius of whatever target it's called upon, to the point of killing evacuating civilians in case they're harbouring pirates or something. No way that'd be called in upon a prison island. Also, save some very rare exceptions, exactly ten people in the world have the authority to make a Buster Call, and none of those are actually present. So.
I mean, apparently all those living on island are dead or missing, prison is already destroyed, and this 50 years after One Piece. Most likely all 10 are dead. Which means we have a new generation with the power to do so.