Everyone needs nutrients they can digest. The source doesn’t matter under these conditions. Excluding rare medical cases, everyone can get all required nutrients from non-animal sources, ergo everyone can have and live a perfectly healthy life on a vegan diet.
Meat has more than just protein. It has so many micronutrients that your body needs that you would have to take a shit ton of supplements to just come close to it. Sure, you can survive without those micronutrients. But why go through all the trouble?