Eating meat is considered in most scientific thoughts as an evolutionary trait that occurred due to humans’ original nomadic nature. Meaning it was easier to hunt an animal for food than having to replace energy and proteins with plants. Plus at the time meat was introduced into the human diet, we would have had to compete with grazing animals, and edible plants were scarce. There are many good alternatives to meat, and I personally agree that cattle industries have gone too far in many regards. However, meat is still one of the easiest ways to give yourself the nutrients required for the human body
What I was getting at is that it’s harder to fight evolution and it takes time. Advocating for meat free lifestyles would most likely push different evolutionary traits in a few million years. And you have to consider cultural influences as well. Additionally, veganism is more prominent in higher income countries because of food processing and “health food” taxes cost money, so many vegan items aren’t inexspensive. Those people that are too impoverished to afford a full vegan diet would starve without meat. Also consider those places where the land can’t be fertilized and farmed. Those people as well would starve. Trade could resolve that only if they can afford it.