I'd imagine that such a future also means that a lot of the devices capable of what you say would be made "illegal" by virtue of countless regulations, requiring of licenses and approvals, and even grey-areas that make it a nightmare for private individuals to pursue, etc. I phrase it like that, because all of these things (though some may be noble/necessary/etc) do effectively make things "illegal".

You can essentially already do this with a Raspberry Pi, PiCam, battery pack and opencv. The hardware will cost you under $100, and there are already various libraries that can process the license plates [0]. With a 3g stick you could even collect this data remotely.

Of course, performance won't be comparable to the commercial product here in question, but I'm certain that with some motivation you can get similar, if not better, results on better hardware.

[0] https://github.com/openalpr/openalpr

With systems like this in place do you really believe anonymity is even an achievable goal?

It's a good point. At the end of the day, anything you do in this universe is observable :)