Well maybe its that you dont understand the hydrodynamics of what entails 'hull speed' .... the underling tech definition is the speed of WAVES generated by the moving hull as a functional result of the sqrt of the length of the hull, not the speed of the apparent max. speed of the hull which is the dependent variable - a resultant.
Theoretical hull speed was covered in first year hydrodynamics and ship construction, along with the various methods of cheating it; bulbous bows, SWATH hull, semi planing hulls, planing hulls, excessive amounts of power, but I've always found theoretical hull speed to be a reasonably accurate limiting factor to speed with regards to conventional full displacement hulls.
Hull speed is not an absolute limit, but indicates the point of diminishing returns for speed gained vs. applied power for boats in displacement mode.
There are curves routinely available for many planing power boats that show fuel consumption vs speed. Typically the fuel consumption rate climbs as speed is increased beyond hull speed and then falls off as the boat gets on plane.
First it is a real number that is actually derived from real measurable physics. It is a function of the S/L ratio of free running waves in the open ocean, and Frouds numbers. It is not meaningless.
Well Rich, I'm pretty sure I do understand hydrodynamics. It says so on this piece of paper on the wall over here (Webb Institute '82) and is implied by this patent on towed bodies in the filing cabinet.
Back in the day when hull forms where all very similar we used empirically derived coefficients for a lot of things. Hull speed was one - 1.15xSQRT(waterline (ft)) = kts. As hull forms became more diverse there were a number of interesting attempts to take a lot of full-size and model data to correlate other characterizations (block coefficient, prismatic coefficient, Δ/L, and other more complex ratios and ratios of ratios) to the hull speed coefficient which is why you'll see multipliers between 1.1 and 1.4.
All of this neglects the fact that hull speed was never and is not a hard wall. It is indeed a fairly big region where the speed-power relationship curves up so that the power required for an incremental increase in speed increases dramatically. The region is a curve, so the rate at which the incremental power requirement increases itself increases. It's like the relationship between distance, speed, and acceleration. Naval architects used hull speed as a mechanism for comparing one platform to another not as a prediction of actual speed, although in the early days of steam it was a component (but only a component) in power plant sizing.
Fortunately as hull forms became more and more diverse our understanding of hydrodynamics continued to improve and other approaches pushed "hull speed" into the background. Model testing was part of that but far from all (which is the only application of Froude number, which relates to scaling between models and full scale). Over the last 50 years computer modeling has completely overwhelmed any other measure of the speed-power relationship.
Bulbous bows do decrease wave-making resistance, independent of "hull speed." Stern bulbs can do the same for low prismatic forms.
SWATH, like other catamaran hulls, take advantage of high L/B forms which are so far off the map of "hull speed" that they in fact demonstrate the limitations of simplistic parameters like hull speed.
Planing and semi-planing hulls work in non-linear regimes where "hull speed" just doesn't apply. Yes you need a lot of power to plane, but if you look at the speed-power curve you will see a real knee in the curve where planing begins (ish) that looks nothing like the region at "hull speed" for displacement hulls.
If you still aren't sure, consider all the 40' boats with "hull speed" around 6 - 6.5 kts that easily sail at 8 to 10 kts. Sails generate a tremendous amount of power.
"Hull speed" only has meaning when comparing boats of geo-similar hull forms.
The way that most people use it is meaningless.