Lets look @ this post in segments. I do not have the facts as to "most common use" for compact tractors, and rotary mowing may well be on the list. However, loader functions, finish mowing, snow removal, site grading, are just a FEW very popular tasks.
I have not "surveyed" multiple dealers as the failures that befall these tractors, doubt you have either, perhaps one, or two.
The point is I never stated the failure is immediate & sudden, but rather the heat aspect takes a toll, explained below. The dealers do not arbitrariy test for system efficiency, unless there is a specific complaint.
Prefer you do not twist my words, requires repeating, never stated that the excessive heat caused by over taxing the transmission through temperature, caused sudden & immediate failures.
This heat affects the components, such as the shaft seals on the pump. Believe Kubota uses the same seals in the system despite using their synthetic lubricants. Why is this relative
I have read that high temps, even synthetics, thin excessively, additives breakdown, & may not recover upon cooling. The end result is the pump still circulates the fluid but a portion can bypass said seals and pump components. The oil viscosity (resistence to shear) of the fluid is what converts pressure into rotational torque. This component wear is not sudden & immediate as noted but does reduce the force exercted to the ground over time. Yes, everything wears over time, the subject of my posts is that this wear is excelerated by high transmission temps. (Pushing the tractor reasonable limits)
Again, never criticized the HST concept, I own two. All of this subsequent nonsense stems from my post that rotary mowing in hot weather, through heavy grasses &light brush, causes high transmission temps. I specifically suggested to select cooler portions of the day for mowing while abstaining from long mowing durations to reduce HST wear. I further noted that gear driven tractors fair better for this task.
From there the keyboard cowboys wish to make this a hill to die upon.
Some folks have the delusional belief that comments posted on these forums have some gospel like impact upon wold affairs. Except for Dave in Ontario, not sure any of the authors here are practicing engineers, employed in engineering divisions of a tractor manufacturing company or have articles/books published in applicable & recognized trade journals or the library of Congress.
There is helpful information to be had herein but few, very few of us, yes myself included, are credentialed "experts"