Any number of companies sell cameras and recorders both on-premise and cloud stored which are managed entirely by the customer. Most security cameras you see on any given building work this way, and most such camera systems also support features like LPR (license plate recognition). Most of the time you're on your own to sort out connectivity and power though.

What Flock is selling is the whole package: The hardware (including power, networking, and the pole), the software, the infrastructure, the logic design, the connectivity. For someone who doesn't want to operate and support a wide area network of IoT devices, you can see why "just give them money to watch your streets" looks appealing.