To some extent, that could also be used to explain why rivalries from New Square took a seeming hit in this format - for instance, Final Fantasy VII is not about Cloud vs. Sephiroth to the extent that the Mario series is about Mario vs. Bowser or the Zelda series is about Link vs. Ganondorf.
In the latter case, Link and Ganondorf don't meet that often, sure, but technically most Zelda games are about building up to a final showdown with Ganon as far as the plot goes. Compare that to a Final Fantasy game, where there's generally a lot more going on than the mere conflict between hero and villain, or to a Metroid game, where Ridley is just some guy who appears by surprise and as a result, that's a rivalry that only hardcore fans of the series would understand - although clearly Metroid is a franchise that lives and dies by its hardcore fans.
I don't want to do much analysis on this, but I came up with all this pretty quickly so there.
--
Currently Playing - StarCraft: Brood War