Remember also that Cronk and Zephyr were originally meant to represent the PS3 and Xbox 360. So, in a way, their deaths represented the end of the 7th generation of consoles. (Even more fitting if ITN is the last R&C game on PS3.)
They were supposed to represent Xbox 360
They were supposed to represent the console wars. They're always arguing about who's better.
*cough* PS3 *cough*