The cost of reviewing video with nothing going on IS free, as even the cheapest camera will only show video where there is motion detected. I would bet the average single family residence (with no kids) probably has less then 5 minutes of motion at the front door and driveway during a day. Fast forward and your time is now down to close to nil.
Add to this the rapid development and falling cost of machine intelligence with video processing and you are looking at the beginning of a totalitarian "video state". The technology exists to use video surveillance to use facial recognition and processing of objects to automatically issue citations for j-walking or littering. I bet we could think of hundreds of other profitable invasive uses that are possible. Of course people (sheep) say, "Oh they would never do that." And a few decades ago people would never have believed that the government would have the ability to look at every purchase transaction that people make, and they certainly wouldn't have believed that "The People" would ever stand for that level of intrusion. But you have a credit/debit card with you right now and using it doesn't make you flinch.
Governments nowadays ALL coin the phrase "sources of revenue". What this means is the people working in government see the citizens that they are supposed to serve as their source of $$$. The fact is that government cannot resist getting their hands on more money (numerical unit of power).
The law used to be a framework where if someone caused a problem they could find a way to deter them from being a problem. There was no intention of enforcing all laws 100% of the time. Now when something happens the agents of the government never ask, "Should we apply this law? but instead only ask, "Can we apply this law?". Add this to the endless search for more revenue and you have a future where the video camera sees you drop a $5 bill, detects dropped paper, and the facial recognition system mails you a $1000 littering fine.
The endless creep of intrusion is headed that way and unless something huge happens it will slowly become the norm. But thank god!!! It will make you safer!!!!
But safety is a FEELING, especially when it doesn't come with a real percentage of improvement in life expectancy. And LIBERTY (all in caps!) is a RISK and it always was a risk. A risk that a lot of people died for.