What Columbus did discover was not America per se, but a replicable and openly published route to America. And that's what made him justifiably famous. The day he reached the New World was a significant event, but it wasn't really important until he showed that he (and anyone else) could do it again.
It may be going too far to suggest that no one should ever use or accept experimenter-made measures, no matter how fair they appear to be to the experimental and control groups. However, what it does say is that we need to be very cautious in accepting experimenter-made measures.
I've had many conversations with proponents of making VAM a defined percentage of teacher evaluations, and not a single one has been able to explain why their approach to VAM is better than an alternative approach that focuses on aspects of teaching practice.
Lighthouses once guided ships to safe harbors, but in education, policies limited to finding and celebrating lighthouse schools are less likely to improve outcomes more broadly. They may lead policy in a good direction, but they may just as likely guide us onto the rocks.