Anyone else surprised the generations look so remarkably similar? All of these models have “independently” generalized that the moose should roughly be standing at the same position (left) or that the giraffe should have a certain color palette.
More-generally, I suspect an influence from how left-to-right languages (i.e. English) affect comic layouts. Overcoming that bias often means using vertical space to exploit the top-to-bottom habit instead. (Consider the rarity of an English-language comic panel where action is from bottom-right to top-left.)