It might be that a new market has been found (so to speak). If stealing Apple stuff gets a good return then it may be that previous targets are not being hit as hard as they would have been, with the extra energy being direct at Apple owners. It would seem to me that the potential gains from mugging someone today would be significantly higher than 10 years ago - phone tablet and laptop are all commonly carried at same time by people in this room with me. Even 5 years ago this wasn't the case.
From the article,<p><i>The series of Apple-product thefts has been challenging the police for several years, but this is the first time they have been seen as significantly skewing the crime statistics. “If you just took away the jump in Apple, we’d be down for the year,” Mr. Bloomberg’s press secretary, Marc La Vorgna, said.</i>
Wouldn't this imply that people who would otherwise not steal are stealing Apple products? If it were otherwise, the Apple thefts would simply be spread out among other targets.