Hi Janie: welcome to HKOoutdoors!
A few years ago, I asked someone why pretty much no one lives there anymore – he told me that in 70s, there was a spate of robberies by people from mainland (where times surely tough), and most moved out.
Likely also linked to deceline in farming in HK, as cheaper produce from elsewhere – more remote villages typically emptied out, or like Tung Ping Chau only v few residents left.
(Also asked about smuggling, which I’d heard used to be pretty common there: “that doesn’t happen anymore”)