i currently own a small cattle farm in rural australia and you are correct collars really are not a good solution not only do they rub on things but they love chewing on things especially rubber or plastic wires and electronics they would 100% chew on each others collars. We already use rfid ear tags which are small and unobtrusive and they still manage to occasionally rip those out, rubbing on things. If you were mustering a herd on a large holding say a few thousand hectares this could possibly be of some value at least in initially finding the herd however at least in my country if you are on a multiple k hectare property there is a good chance you wont have any sort of mobile coverage, also cows are creature of habit they have there daily grazing route they eat one place rest in another depending on time of day and weather conditions farmers typically know this. I will also add that the value proposition I have seen with other smart tags that are actual ear tags that do temp / heart rate etc etc does not add up at least with my small holding. the price per month of $5 per cow would eat into the already somewhat slim margins, the data is great but it isn't anything i would not notice by visually checking stock daily. im very skeptical on the faas model in general. Farmers at least in my country would balk at spending that sort of money a month that doesn't directly add very much in the way of weight / condition per month, at least from a beef cattle stand point. (perhaps on a prize bull you could justify the monthly fee)

$5/month/cow sounds insanely expensive.

5c/month/cow sounds more reasonable. Which in turn means your hardware needs to cost only a couple of dollars and last many many years.

Very much this. Even more with places like ours where all of our cows have horns (highlands). I can see all sorts of bad things happening when two cows get hooked together when a horn slips under another cow's collar.

Add to that, my wife can gather and guide the entire herd with a bucket full of cubes, or every even random junk in a pinch to get them to go anywhere she wants whenever she wants.

I don't know much about cattle or dairy farming, but in Switzerland cows are running around in the mountains with big bells around their neck and horns on their heads. Would such a collar really be that dangerous for them?

Open pastures are pretty safe, but as soon as the cow comes in contact with a gate/fence or other man-made objects (...milking parlors) they may have issues catching the neck band.

The bands also look poorly-suited for interfacing with the standard lockups used for artificial insemination and preg-checking.

Our dairy cows have activity tracking (heat detection/poor health detection) collars, and they work fine with lockups. The cows do turn their head a bit differently to make sure the collar clears, but they learn quickly and we've had no deaths yet (200ish cows, 5ish years of using the collars)

Yes getting in and out of a stanchion is a scary experience for the cow and human both! Adding a chunk around the neck that could make entering and exiting more difficult can pose risks for both parties.