I can generally agree with what you said here. I do not think it negates my point though. My point was not to argue for anyone using a specific bar height, but that they should consider using something similar to what they use on their road bike. They just might find that higher bars may not allow more comfort and may actually cause more back and butt discomfort.
On the distribution of weight... I'd argue that a large portion of the rider's weight should be supported by their legs and sitting upright does not promote that in my experience.
I concede that there is a very broad range of what works for a broad range of individuals and that I am probably pretty close to an extreme end of that continuum.