Dai Pai Dongs are so rare and special in Hong Kong.
Currently not many people own a license to operate a Dai Pai Dong. Among those that have the license, it can only be passed down to their spouses. This is why Dai Pai Dongs is are slowly diminishing number.
The decreasing number is due to government intervention when Dai Pai Dong was the cause of many problems like traffic congestions and the obvious lack of hygiene.
Most Dai Pai Dongs I see these days, either, now operate in food centers to survive or they own a stall and lay out tables near their stores.