My opinion for what it's worth...

The Final Fantasy Games seem to take quite a bit of "reality" into their story lines. Specifically with FF7, there are elements that completely resemble Earth, but not a futuristic Earth. I would say that the technology in some cases is about 30-50 yrs old but the society itself is less advanced. Also, the lack of population, (only so much can fit onto 3 cds), indicates a newer or early society that may be developing into cities and states. It's like early Rome or Greece but with 1980's tech and clothing. I think FF7 is a unique blend of Japanese creationism myth, coupled with a realistic Earth like population and fantasmal inhabitants and abilities. If you enjoy Sephiroth's Supernova summon as much as I do, the American version of the game I mean, you can see the other 8 planets named specifically. Doesn't get any closer to our Solar System than that.

Kage