I'm having trouble understanding what you are even getting at with comparisons to astronomy, where the absence of controlled experiments isn't some grand innovation astronomers cooked up but a basic constraint imposed by studying stuff that is light years away. Any decent epistemologist would tell you that the character of knowledge generated by astronomical observations is of a lower quality than that of a RCT. I'm sure some astronomers or cosmologists would give their left arm to do a randomized controlled trial!