> That is what happens if C is developed after B becomes the standard treatment, D after C etc.
Can you point to particular drugs or are you also making up examples?
I admittedly do not know of every trial that happens everywhere but this is exactly the sort of thing that a layman expects would occur but which does not happen.
Stem cell treatments come to mind. Outrageously expensive (or outright unavailable locally), in many areas and for select purposes.
> Stem cell treatments come to mind. Outrageously expensive (or outright unavailable locally), in many areas and for select purposes.
I don't see how stem cells relate to the idea of trials for successive standard-of-care treatments. Can you explain your thinking?