It’d be hard to keep individuals from doing this. But individuals aren’t running networks of cameras. Companies are. Those companies probably couldn’t fly under the radar selling LPR data if the practice was banned.
Most individuals I know only have access to a handful of places they could put ALPR devices. Their home, their work, a couple of really really close friends who trust them enough to let them setup a camera on their property. Individuals could pay people to host their cameras but then that starts looking like a business, so while it's theoretically possible for an individual to have a network of APLRs just for the fun of it, that just seems like weird enough hobby that, I don't have any evidence of this, but I don't think anyone is doing that.
You can ban the commercialization and mass scaling of the technology. Just because you can't prevent something at a small scale doesn't mean you can't prevent corporations and government agencies from doing it without exposing themselves to unacceptable legal risk.
There is little chance I could just post up cameras wherever my ex travels and note all the time she arrives and leaves at all intersections and get away with that without at least a restraining order ordering me to stop. What they are actually doing is stalking by method of a network of cameras deliberately installed to follow people from place to place. It isn't generalized observation in pursuit of speech, it arguably isn't even speech, but rather mass individualized stalking. Maybe 1A allows that but that doesn't seem to be the law on the books for anyone else trying to stalk people in such a way.
Personally I don't have a huge problem with 1A being broad enough to including recording literally everything in public and meticulously cataloging and following everyone, but only if the rest of the amendments are read in the same broad and literal manner. Meaning I can own nukes, I don't have to display a plate, the 10th amendment would stop the feds from outlawing intrastate weed, etc. What it looks like what happens is the feds cherry pick interpretations of the bill of rights to trump up their powers and then give the least charitable interpretations to the plebs.
https://gc.nh.gov/rsa/html/XXI/261/261-75-b.htm