IMHO the physical markets are becoming less relevant. Relatively little R&D occurs around these areas now, the majority of such operations being in the shiny Nanshan district, various outskirt districts or in nearby cities such as Dongguan. The chief drivers in this shift appear to be efficiency, the rising cost of real estate and salaries in Shenzhen, and the availability and cheap fast couriers (you can pretty much order anything online and have it arrive next-day). Therefore, the markets have tended to generally shift toward consumer retail and finished products and away from electronic components (although they are still present).