“In short, brain death with the lungs being able to breath on their own, does not exist.”
correct. by definition If someone is breathing on his own he isn’t brain dead.
“I thought the resistance to using brain death today, is a fear of hospital bias.”
That is partly true but a very low extent, and easily remedied, (eg. devise better tests, use multiple doctors to assure done correctly etc) . The bigger issue is most poskim hold if the heart is beating (which a brain death patient’s is) the person is alive (or safek alive ) even if the brain isn’t funtioning and even if patient isn’t breathing