The old "acceptable oil consumption" charts date back to the middle of the last century, and they exist in the automotive world as well as at Harley. They were originally created to provide guidelines for the dealers and to prevent them from attempting repairs and submitting warranty claims for issues the manufacturers considered to be acceptable. Back in those days, oil consumption was normal thanks to the limitations of materials, machining, etc., and the charts reflected consumption that could occur even when all the parts were within the tolerances common in the day. However, since the 1980's there have been massive improvements in materials and manufacturing processes, to the point that we have engines in the auto industry these days that require much less maintenance and are much more reliable. It's not uncommon for an engine to go a couple hundred thousand miles with nothing more than scheduled maintenance, as opposed to the fifty thousand miles and an overhaul common back in the day.
The consumption charts still exist, but no one believes or accepts the conclusions of those charts in the auto business. Only the most anal service managers try to blow that smoke up customers butts, and those who try often find themselves on the losing side of a lawsuit. It's well past time for Harley customers to also stop accepting BS. They are paying just as much for a Harley as most people pay for a car, and they should be able to expect industry standard quality and reliability. A properly assembled late model Harley engine should be more than capable of running five thousand miles without having to add a quart of oil. The fact that many cannot do that is due to poor decisions and poor quality control at H-D, not any technological hurdle imposed only on H-D.
Jerry