First let me clarify that we don't study cholesterol-lowering drugs at the University of Victoria. There have been 14 major studies of the major cholesterol-lowering drugs. Why are they still being used? The answer is complex, but you might want to read the first chapter of my book about cholesterol.
The main thing is that the power of the market is so intense that it overrides anyone who raises concerns, anyone who points out lack of data, and anyone who essentially looks closely at the data and finds that those drugs aren't as effective as the manufacturers say they are.