A few more articles from 1903, 1904 and 1906 showing the Wrights plane with a propeller underneath.
Cool. But so what?
Perhaps the first illustrator believed that such a propeller was required and later illustrators followed the first one's lead. Perhaps the Wright's were happy to let the newspapers draw somewhat fanciful representations of the airplane, even guiding them to do so, so as to confuse and annoy the competition. Who knows?
The successful flights that the Wrights had in later years would lead one to conclude that they got there through success in earlier years - even if their efforts were not sufficiently public for your liking. Kind of like how the street being wet is evidence of it having rained.