I see some major drawbacks for things like this:
1. Because of the way cows behavior naturally they will get their neck band caught on something. Extrication can become dire and stressful. A few deaths and a system like this is simply not worth it.
2. These will be roughed up -- like a lot. Cows like to play in water and rub on things. If this company doesn't last you'll be SOL quick enough that your initial investment won't pay off (saying nothing of software dependencies...)
3. The point of interacting with cows manually is to see her. Even in herds in the 1000s someone familiar with the herd will recognize cows (especially past problem ones) and can also see issues before they become a risk for her.
Cows are very well adjusted to being taken care of by humans. Everytime you back off the human component from herd management the domesticated cow will be less cared for.