Cosmological solutions are the work of crank physics. There isn’t any plausible scenario that involves reduced gravity.
I don’t have a solution, but the simplest guess is simply that the weight estimates for these creatures are way off.
It’s amusing that creationists are quick to criticise paleontologists for extrapolating entire creatures from a few bones, but when such extrapolations suggest that Newton and Einstein are wrong about physics — hey, let’s scrap physics.
I agree that gravity didn't change much since the earth formed as a giant, red hot, roiling, boiling sea of molten rock about 4.6 billion years old. Roughly the same mass, give or take a factor of two the same diameter, and always the same gravitational constant.
But ... why do you dismiss the "faster spinning" possibility?
So, let's see, you'd prefer to trash the Square Cube Law... Something that is based very firmly in physics, engineering, and mathematics... so you can ignore a real observation. Notice it is called a "law." That has a little more weight than "theory." It tells us WHAT we have observed in every instance, no exceptions allowed... that's what makes it a law. A theory will tell us WHY it may do it.
Are you postulating that these mega-fauna, all of them, have large bladders filled with hydrogen to offset their mass? They're made up of some kind of matter that no longer exists? Were their bones the consistency and density of balsa wood??? Perhaps their muscles were made of styrofoam?
Some who have wished the problem of how megafauna could have lived would go away have actually postulated that it is the fossils that have grown... that somehow the bones and other remnants of these ancient animals have somehow increased three to four times the size they were in life... along with their ancient preserved footprints... and coprolites (dung)... and eggs... I guess by magic.
Almost every great scientific discovery came about because of inconvenient facts that the accepted wisdom could not account for... and that often the mavens of that accepted wisdom refused to acknowledge existed. Dogma can be a very bad thing.
The problem here is that we have several laws in conflict with observed facts. Perhaps the facts are wrong... but so far I see no evidence that they are. If the mass of the mega-fauna is as described, and the conditions when and where they lived are as we live under today, then several well established scientific conclusions are wrong. Something has to give. Something has to be tossed into the trash. We have to start over and find a Theory that comfortably incorporates the new data.
Cosmological solutions are the work of crank physics.
But, js1138, our current cosmology has FAILED to provide an answer to these facts. That implies that the answers WILL indeed impact cosmology in some way... perhaps to overturn the current accepted cosmology... perhaps to extend what we know so that we have a better cosmology.
Seems to me that Plate Tectonics was the stuff of cranks and crackpots not too long ago... as was the catastrophic explanation for the extinction of the dinosaurs... and the evidence for them was swept under the rug... and proponents were trivialized... as you are attempting to trivialize Holden who is merely insistent in raising inconvenient facts.
You admit you have no solution to the problem presented... but you prefer not to look at the implications of the facts presented. For some reason, some of those implications or possibilities of answers are "off limits" because... why? Because someone who also refuses to look at the problem says so?
To that I say "But still it moves... and flies."