For example in France we're in a permanent "state of emergency" since the attacks in 2015 (and now with covid), which grants more rights to the government/police and let them bypass some legal safeguards for "the greater good" but of course it's already being abused, not against terrorists, but against protesters, people squatting land to protest against projects that would have a negative impact on the environment (https://en.wikipedia.org/wiki/Zone_to_Defend), &c.

Today, it is my impression that much data is only used to reconstruct events after the fact, rather than gaining a priori knowledge to prevent an incident in the first place.

(And, to make it clear - I am not suggesting 'progress' as outlined above is desirable...)

Ratcheting up automation is what would make it different to me. While there are exceptions, for the most part, police look at all this data after they know about a crime.

They have most of what they need to use the info to discover crime and automatically cite people. As a simple example, ANPR in two places could issue a speeding ticket if the time elasped between two scans is low enough. I'm sure it's happening somewhere, maybe a toll road. The difference would be when it's widespread.

But I'm wondering if that really is what needs to occur before we consider a a state to be a complete surveillance state, if, for example, almost every home has some kind of device that can be exploited for surveillance, e.g landline, mobile phone, television, smart devices, laptops/desktops/tablets, internet routers/modems, smart meters, smart heating, rubbish collectoin etc?

I.e. have we opted in to in-home surveillance to a sufficient level to make mandatory surveillance almost of no use.