@Jeremy Ford I'm sorry, but you're basically saying "you don't understand it, it's more complicated", only to proceed to paint a very black and white image full of generalizations.
The fact is that current games, including sims, are rarely CPU limited to such extent for the CPU to be a clear bottleneck. Saying "1080 is wasted with an Ivy Bridge CPU" is a great exaggeration. Yes, at least with some games, the same GPU might perform somewhat better with a better CPU, but that alone doesn't mean it's wasted on an older CPU - the old CPU can (and most often will) still benefit from better GPU, because the question of overall performance is, just like you suggested, a lot more complicated. Plus a better GPU still gives you things like better antialiasing or higher resolutions virtually for free, which is something quite a few people care more about than being able to run a game at 180 fps instead of 145 fps. Will a 1080 be utilized fully with an Ivy Bridge? Probably not, and to what extent, that will depend on a specific game (and on the specific CPU). Would I spend the money on a 1080 with an Ivy Bridge, thinking it's the perfect upgrade path for the money? Probably not, even if I could afford it. But it still doesn't mean it will be wasted either.