Most vegans can’t keep up the lifestyle more than about 5-7 years, as health issues start to creep in.
The diet isn’t as nutritious as they claim, and there is no good replacement for animal fat and protein.
The meat industry has problems. Don’t get me wrong. But they’re not at the same scale most vegans will tell you they are, and as it happens herbivores are much better at turning plants in to energy than we are. Plus it’s not like we’re treating the actual humans picking tomatoes much better than we treat cattle.