Some of those differences may be significant, but many of them are simply propaganda from press agents, museum curators and bankers. Let's investigate.
Here is a herd of wonderful elephants:
Heinrich Kley's elephants courting
Rembrandt
Disney studio's "Pink Elephants on Parade"
Jack Davis, GOP elephant
Jack Davis, study for Time Magazine
You will never see these elephants hanging out together in the same neighborhood; some reside in museums, while others reside in corporate filing cabinets. They were produced by very different hands, centuries apart. They were designed for different purposes and cost vastly different amounts. Yet, these are only questions of pedigree and should not distract the true art lover. As you compare these pictures, you will find we can still judge their most important elements on a level playing field.
A museum curator would faint at the heresy of comparing Rembrandt to Jack Davis, but never let that stop you. Personally I think Davis did a better job than Rembrandt here. His humor is broad, but I also think his drawings of elephants are more insightful and interesting than Rembrandt's drawing.