A British Comedian called Jimmy Carr made the point that up to and including WW2 the Stasi in Germany was massive, it was a huge undertaking involving a massive percentage of the population just to monitor everyone and such a large organisation is going to have a lot of problems. That level of monitoring with todays cameras and software takes a tiny fraction of what it used to and can in many ways be more effective and its getting more effective with every advance in mass data processing and cheaper sensors.