trailers and axle weights?

[packman]

i saw it out west all of the time, pickups pulling flatbed trailers with 10 thousand lb axles, two axles, eight wheels. when i look at the heaviest fifth wheel tt's all i've seen are 2 or 3 axles,[6000 or 7000 lbs]. how do the flatbeds get by with a 20k gw trailer , behind a pickup, and why wouldn't any rv'er want the assurance of more rubber on the ground, and less chance of being dead in the water in case of tire or wheel failure? without getting into the "de-weighting" issue, registration wise, the rv manufactuers obviously know more than the flatbed manufactuers. to put it simply, the axle weights determine the trailers gross weight don't they? two 7000lb axles give me a gw of 14000 lbs, trailer and load. two 10000lb axles give me 20000 lbs, way too much for any one ton, legally. gross of the truck, gross of the trailer, give you the gcvwr, period. 10500 plus 20000 equal 30500 lbs.... huh. buy the way i've pulled a dual tandem trailer for years, 26ft, and this has only come up , well it's never come up, in 13 states, but sooner or later.