I agree that while many economic theories are impractical to implement in reality, they still allow us to see where the bar can be set to in a stylized world. Then the question becomes why can't we get there from where we are today? RCT are no different. Yes, they may be difficult to implement, there may be obstacles and opportunity cost associated with the resourced need to carry them out. However, despite these limitations the information they provide is critical. It is important to know what magnitude of difference a "treatment" can make. Then decide why it may or may not to be possible to implement on a larger scale (i.e. from NGO to Governemnt).