Hate to break it to you: it is that cheap. I an looking at a $99 Intel Compute Stick driving a build of the enterprise FR software I write, connected to a $21 ELP IP camera. Total cost of hardware is less than $150, and the software is of course expensive. There is no reason a button or embedded-in-a-screw camera would not work just fine. Pandora's Box is open kids, and it is not closing.
Deploying and powering all of it at scale, not to mention getting bandwidth (so you'd need to set up a mesh network or get very cheap mobile data) is still out of reach of most. When that is sorted we can revisit.
Hate to break it to you again: the cameras and connection networks are already there. Also any real estate property of note had a traditional camera surveillance network added sometime over the last 30 years, and modern FR systems are designed to piggy back on them. Just add the less than $150 worth of hardware per camera, perhaps you only need 1-2 FR systems and ability to switch camera feeds and you're operational.
The original comment was about criminal gangs setting up their own surveillance systems to keep an eye on the police (among other things) and the argument was that if the bad guys can do it then why not allow the police to do it as well?
Property owners doing so on their own land is a whole different matter.
I just don't see it happening at a widespread scale yet. On the other hand if you give police the right to use these technologies you can bet you'll see police (and other government agencies piggybacking off them) deploying this everywhere very fast.
