I had a post about cartoon backgrounds but safari for iOS ate it. Why arbitrarily reload a page after a few minutes away?
Basically what I said was: American cartoon backgrounds seem necessitated by the virtuosity of the animation they foreground. They become less detailed but adhere to principles of good design that mesh with the style of cartoon. The cartooniness in American 40s/50s/60s animation is borne out of this same virtuosity, the animators' full use of the syntax of animation.
But I also wanted to point out that besides the famous more "artistic" heavyweights, Mary Blair, Eyvynd Earle (sp??), etc., there were a lot of interesting minor background/layout people: Maurice Noble, Art Lozzi, Bob Singer, etc. Their work was far from soulless!
There were times when Chuck Jones took cartoons off the "good design" deep end, when they became too planned and fastidious, and I think he had a bad influence on cartoons whereby his influence made them less funny, more sitcommy, more genercized, and more beholden to design/beauty rather than humor. I think Chuck Jones' influence ultimately led to the very un-Chuck-Jones-like generic town-and-country backgrounds with exaggerated proportions that you see in 90s "cartoony" Saturday morning cartoons; and UPA and Jones both are responsible for the horrible "designy" backgrounds you see in Dexter's Laboratory and its inferior imitators.