In every conversation I've seen, this accurate fact has been the primary counterpoint to the idea that a plant-based diet is more sustainable, but what percent of the world population lives a nomadic lifestyle in the arctic steppes? I don't see even the most hardcore vegans running social media campaigns aimed at coverting remote nomadic cultures to vegetarianism. They tend to focus on middle class white people who have more options available to them. Also, reduced meat and fish consumption by rich people would leave more healthy ecosystems to sustain those who depend on them.