"What if Toy Story was put out with bad poser 3 lighting, and horrible, clunky animation?  Would it have been nearly as successful?"

What??  Toy Story???  If you do cg for a living then by all mean use Toy Story as a yard stick for your own work if it makes you feel good.  But for a hobbyist that's a patently ridiculous notion.

" I just don't get why someone wouldn't take the time to make the art as good as the story."

Because they're hobbyists and not doing cg for a living.  I'd much rather do several hundred "mediocre" renders than a dozen "perfect" ones because my only intent is to have fun.