I worked as a genetic engineer in human cell therapy: developmental biology doesn't really work that way. You can't just "decephalize" without causing massive secondary effects in body development and maturation - the nervous system is very much a central part and organizer of animal development, and also centrally important in a lot of the physiology you want to test when doing drug trials! And good luck keeping decephalized animals alive long enough to harvest outside a sterile lab. You don't need to be an edgelord billionaire to make a difference, but you'd benefit by learning more biology.