Key to Hikvision's success is billions of dollars of Chinese government projects (one example here).
Hikvision explained how they work:
Among them, the first-tier cities have entered the so-called “third-generation safe city status,” whereby all devices are interconnected, all images are high-definition, and all parts of the cities are covered, leaving no blind spots.
“What this means is that, for example, when you walk on the street, you leave a trail that will all be recorded in the system. And, as these video data are high-definition, your physical traits can be recognized and analyzed,” [Hikvision] said.
That's a safe city or a totalitarian one?