Devil's advocate time:
The rehashes we typically get (ie, crystal, emerald, platinum) are essentially the same as GOTY versions of other games (base game + DLC preinstalled). When you buy the 3rd game of the generation, you're buying something that's 95% the same, but with a couple new features like maybe slight tweaks to wild pokemon distributions, battle tower, move tutors, leader rematches, etc.
I hate the fact that they always leave out the good stuff for the rehash. I'd honestly prefer it if I had the option to just add that content to X/Y for a couple bucks rather than buying Z (ie, a game that's 95% the same). If DLC is simply the content that "turns" X/Y into Z, I'd be okay with it.
I doubt that'll happen though. GF and ninty do everything they can to siphon money away from us. And that also assumes they go back to the C/E/Plat 3rd game rehash instead of actual sequels like in Gen 5.
