aj, if you don't believe me, go put a scale under the tongue jack on any normal tandem axle trailer. Measure tongue weight nose up and nose down as far as the Jack will go.
Then take the front wheels off and compare tongue weight and then take the rear wheels off (after reinstalling the fronts, to be clear) and check the tongue weight.
Once you verify what I said, come back and dispel your incorrect myth.
I'm not making this stuff up. Go take a Statics course and begin to understand moment arms and X-y-Z components of force and you'll see.
You can even do the same with your single axle example with very light tongue weight, save for the one axle vs the other thing. You'll find the same thing applies.
Thanks for playing.