Thinking back to living in Toa Payoh (now enjoying last night in SG (for a pretty long while )in a hotel.) There is the outdoor Toa Payoh Mall with about 1-200m of small retail units on a promenade that dog legs around a right angle to another similar strip. In front of these units are unenclosed stalls run by separate vendors. Together with the other strip between KFC and Courts are about another 100 similar retail units. In total there must be something like 3-400 retail units.
Off the top of my heads I'd estimate half+ of the retailers sell mobile phones and/or accessories.
This seems extraordinary, especially as you seem to rarely to see people in these shops. Is there an answer as to how many retailers can co-exist?