But, for example, if they used the Modern Age version of other Wonders, the Mausoleum, Colossus, Great Library and Pharos lighthouse wouldn't have any visible graphic representation at all, and we have only vague descriptions of what the 'peak version' of the Mausoleum, Colossus or Great Library looked like at all.
Consequently, I'm fine with using a graphic representation that is Distinctive, even if not completely accurate for all periods. The alternative would be either to change the graphics for each Age to represent situations that may or may not happen n the game, or simply leave out the majority of older Wonders for lack of any way to depict them to a consistent scheme of graphics.