One of the big controversies is that these companies do have access to cameras on private property, using things like ring doorbell cameras.
And depending on conditions, you can still track the movement of something smaller than a pixel. Smaller than a pixel doesn't mean invisible, it affects the color of that pixel and you can track the movement of the disrupted pixel.
And you have to actually get close enough you the camera lens to damage it, so there is continuity; they're not just looking at a strange color pixel and leaping to the conclusion that it is a drone, they see the drone flying off into the distance (in reverse) and cross reference it with other cameras to track the movement at a distance.

It's a lot of effort, but protecting the investments of the wealthy is one of the only things that will mobilize both the finances of the wealthy and the actual effort of the police.