Again, at this stage you're just assessing if the treatment even works. The point isn't to fix one group and screw over another, the whole point is that you don't know if the drug is going to do anything. It's much easier to tell if a treatment is worth giving to everyone if you first do the correctly controlled trials.
It seems like you're coming at this from a place of assuming the treatment is going to work from the get go, which is not true for the majority of treatments that undergo this kind of trial. Moreover, many treatments have side effects that, again, are much easier to look at if you can compared them to a group that went through the exact same handling. Even small, seemingly innocuous things like going to a hospital to talk to an interested person about how you're doing can have an effect on health readouts that may be relevant to a study. Or maybe the stress of sitting down having this weird hat put on your head affects something. Or maybe some much less obvious aspect of the study. The point of the control is that you cancel out all of these kinds of effects, obvious or otherwise, so that the ONLY difference is the treatment.
Controls also help with allowing double blinded studies. If the researchers know who is receiving treatment and who is receiving placebo, they can unconsciously influence the results, especially for things like behavioral surveys that aren't as objective as, say, taking blood and seeing if you have more or less cancer cells. Obviously you can't have this kind of blinding if the researchers know every single person is getting the real treatment.
The control group doesn't need to be treatment-free.
But, you are right that sometimes the 'control' portion of a study is halted and the control people are given the treatment if a study seems to be going especially obviously well, on ethical grounds.
It can be some difficult ethical decisions. But whether you have 40 people in the experimental group and no control group, or 40 people in the experimental group and 40 people in a control group, you still only have 40 people in the experimental group.
Not having a control group doesn't somehow get the treatment to all effected people in the world. And it would be unethical to give the experimental treatment to everyone in the world _before you have evidence of it's efficacy_ anyway. It might be ineffective, it might even make the condition _worse_ or have other dangerous side effects in addition to being ineffective. You don't know this until you study it properly. Studying it properly means using proper valid statistical techniques, and may mean having a control group. I think it is unethical to give a treatment to people widely _without_ having done a study with a control. Being a part of a research study can be _dangerous_.
Anyone that participates in a research study, knowing the risks, is providing a valuable service to everyone else that may later benefit from what is discovered, whether they end up in the experimental group or the control group. They are taking on risks of a still experimental treatment to help get knowledge to help others.
I'm not saying it's simple. I'm just saying that it is definitely not as simple as thinking having no control group is somehow more ethical than having a control group, or that it's good idea to widely distribute experimental treatments which haven't yet been properly studied. You will harm people by doing so.
That's my dispute. We know X will kill you in a certain time frame. We have thousands if not millions of data points. I fail to see how the control group is really telling you anything you do not already know. Ignoring what we already know is unethical.
It is just is insane that we set people up for false hope and watch them die in droves. I guess it looks better on the marketing material to doctors. I wonder how many actual studies are halted because of die off in the control group. It sure seemed like that wasn't going to be an option.
I don't think you understand the purpose of the control group.
It is irrelevant how much we already know about what Alzheimer's disease does, because the control group is not intended to tell you anything about that at all. The justification for the control group is not that it will tell us something about what Alzheimer's does.
The purpose of the control group is to determine if the treatment works. That's it.
You seem to be suggesting that when doing a research study of a new treatment, it would be unethical not to give this treatment to everyone on the planet who has the disease. That makes no sense at all. The experimental treatment may do nothing for them, or may actually harm them. Giving an experimental unproven treatment to everyone would be unethical.
If you want to argue that it is unnecessary to have control groups in an experiment, you need to first understand what the purpose they are said to serve by those who believe they are important (which is pretty much any statisticians or methodologists).