Cattle eat more plant calories than the resultant meat. All those plant calories include the “vegetarian suffering.” Purely grass fed meats with no farming will be too inefficient to provide meat to everyone.
Sure meat might become more of a luxury than it is now, but in a calorie to calorie trade off grains have a higher animal kill rate than grass fed meat. I don’t many people are aware how many rodents are killed harvesting and storing grain.
