I worked in pharmaceutical development and absolutely agree on the labeled dosing point. When each arm of your study costs X00 million dollars and Y years, you dont optimize dosing intervals. Moreover, there is no global optimum due to biologic variability in patients. Some patients are flat out non-responders, and some tolerate dosing intervals 10X the average.

That said, there is nothing magic about aligning the half-life and interval. 50% isn't a minimum concentration threshold for efficacy. depending on the product, it can be anything. Sometimes area under the curve is the relevant parameter. Sometimes you want the product to go under a limit before redosing.

The one part I disagree with is about bleeding edge doctors. Maybe it is my field, but I find doctors to be readily willing to completely ignore the labeling. Statutory protections are high for clinicians operating off label. If someone is interested, I suggest they raise it with their doctor. For most medications, the dosing is far from the individual optimum.