Of course this is a good philosophy and nobody is saying that there is no place for drugs, especially in emergency situations.
As for "conditions that have developed" not being reversible by Carnivore/Ketogenic or other dietary changes as well as other lifestyle changes, I beg to disagree though of course it depends on what that condition is. You might be surprised to see obesity
and even heart disease being reversed(the later is very difficult but possible) by dietary change (leading to weight loss). Just search on YouTube.