As the other user said, I don't believe we could get the political muster necessary to pass a law taxing meat heavily any time soon. Meat is popular! Nobody wants to give that up.

Also, you're absolutely correct that dairy milk is less efficient by a long-shot, I was just pointing to it because I know a lot of people I personally know are moving to it and away from dairy as though it's a quality alternative. It's better, but still not great.