Reminds me if improving process performance, getting from 60% to 80% is easy, 80 to 90ish already hard, 90-95% really hard and everything above 98% is either luck or killing single deviations or both. Not counting for all the new causes that pop up. Anyway, it is an interesting angle, also economic wise. As causes are getting narrower all the time the increasing development costs can be shared by a lot less patients. I can see the incentive of not going after these treatments.