Where did I say that a vehicle with a higher GVWR was better than one with less? I did say that if I had to pick one number, GVWR is the one I would not exceed. As you figured out, some vehicles are closer to their GVWR and therefore have lower payloads than others.
"I can put my family of 6 into a typical crew can 1500, and I am at max gvwr, so my tow ability is nothing!"
That is correct if your figures are right. I see no reason to operate a tow vehicle over its GVWR. Lots of people do.
Here is what GM has to say on the subject, and I agree. (We are not talking legal or family weight):
"It is important that the combination.
of the tow vehicle and trailer does
not exceed any of its weight ratings
— GCWR, GVWR, RGAWR, Trailer
Weight Rating, or Tongue Weight.
The only way to be sure it is not
exceeding any of these ratings is to
weigh the tow vehicle and trailer
combination, fully loaded for the trip,
getting individual weights for each of
these items."