IIRC the issue is that new common drugs for humans contain toxins that are deadly to vultures in high doses. One issue with just creating a vulture sanctuary around towers of silence is that it’s nearly impossible to tell if a person has had any of those drugs and if so how much. Plus in that culture cremation/other forms of disposing of bodies are essentially sacrilege because the idea is that having the body touch the earth, fire, or water would be a bad thing which is why they do sky burials in the first place so it’s not like they can just refuse burials.
