You make valid points on testing antennas, It would be great to have
actual tests that were run with all variables being accounted for.
Looking
at the way he did his tests, is more real world. That is, the way a
typical person would do when the purchased an antenna and put it on their
vehicle. His tests show which one worked best for the testing he was
doing. Which would probably have different results on someone elses
installation.

The trick is to get a feel for the magnitude of the variables that are hard
to control, and take that into account when evaluating any measured or
perceived differences.

The audiophile guys are buying $7500 AC line cords because they think that
it makes a difference in how the sound comes out. (ignoring the same old 50'
of crappy 12 ga wire in the wall back to the box, and the rest of how the
power gets to the house)