Beck was left by people who were perfectly capably of helping, despite evidently still being capable of getting himself down. Your example is good too, but there are many, many examples of people in radio contact with a camp only a few hours of non-technical terrain away, but where the people in camp don't actually do anything in time. Also, being physically present next to the person who needs help seems like a bit closer psychological connection than a radio, but there are still cases of people being left behind due to incorrect evaluation of "futility".
I agree completely, and agree with your original statement that the major problem with Everest is that it's full of amateurs.
I'm just saying that the technical difficulty of a rescue isn't the only criteria. In the case of Minamiura, his survivability if he was rescued was high. The chance of him being rescued was low. For someone suffering HAPE/HACE on Everest it's probably the reverse. I didn't mean to suggest that they should be left behind.