And has anyone raised the issue that if everyone went vegetarian in the world and we stopped meat production with farms and such we would run out of phosphor which we need to provide the population with vegetarian food by 2035~ (source forgotten but feel free to google it)?
This is not an issue. Because there's a huge margin between the current situation, and all the world becoming vegetarian; that's litteraly impossible. And actually, most of the phosphorus we use is mined from calcium phosphate rocks. And there's phosphorus in all cell membranes, wether they come from animals or plants.