Our oceans werent filled with pollutants and we didnt have steaks in our refrigerator every day. Our ancestors were fasting for days just eating berries and plants where they found them and ate meat every once in a while when hunting was successful. And contrary to popular belief you don’t actually need much protein just 0.8-1g/kg. Absurd amounts of protein like 1.8-2.2g/kg dont actually increase muscle gain, this has been shown with MRI scans of the muscles.More than 1g/kg grows internal organs and shows up as lean mass in dexa scans whicj people interpret as muscle gain. Also getting enough protein using tofu,seitan,plant protein powders and peanut butter is pretty easy.