Technological advancement of FFVII's world

[Masamune·1600]

One has to bear in mind, as I believe Big D previously suggested, that Gaia followed a different path of development than did our Earth. While books/movies/games/assorted media with "medieval" or "futuristic" settings can be somewhat characterized by those blanket terms, FFVII presents a relatively modern world, though with technological tendencies that don't parallel ours exactly. Personally, I feel that the Gaia of FFVII was meant to reflect Earth at the time of its release, at least roughly. Again, as previously suggested, Gaia has some technology that we don't; we have some technology that Gaia doesn't. While I realize the point of this thread is to quantitatively determine the relative advancement of Gaia (apparently in terms of our Earth), I honestly feel that Gaia is, in this sense, meant to be a rough approximation of Earth circa 1990-2000, only (once again) with a different path of development.

though by the time of AC they've pretty much all been destroyed. The only tech-based energy weapon we see in the whole movie is Barret firing his laser cannon at Bahamut Sin.

Actually, very mild Advent Children SpoilerBarret's "laser cannon" used against Bahamut TREMOR is a Limit Break, probably a reinterpretation of Big Shot. That's beside the point, though; a fully functional artificial hand that can unfold into a powerful weapon is itself emblematic of some fairly advanced technology.

materia-equipped robots

With the obvious exceptions of Cait Sith No. 1 and Cait Sith No. 2, robots do not seem to directly utilize materia. Materia is, ultimately, crystalized Spirit Energy, and the fact that robots, as manufactured, inorganic creations, do not have Spirit Energy would seem to preclude such use. While Cait Sith would seem to be an exception, one must remember what the starter manual to FFVII suggests.

Cait Sith rides around on the back of a huge stuffed Mog he magically brought to life.

Not only does this suggest that Cait Sith's origins were different than those of other robots, we must remember that almost every robotic enemy encountered in the game seems to operate via artificial intelligence. Cait Sith is Reeve's vicarious battle incarnation, and as such the ability to use materia is probably derivative of his Spirit Energy.

It's very likely that Mako-related technology could have been employed, but robotics in general probably doesn't use materia.

The war against Wutai seems to be the only big human conflict in the planet's history, aside from Jenova's first appearance and the various skirmishes fought by or against Shinra.

I wouldn't say that the war against Wutai was the only major conflict that VII's world has ever had. There are at the absolute minimum, 2,000 years of human history in FFVII to work with. In only the last six thousand years of our history, there have been about 15,000 wars; if we assume an equivalent average war per year value, that comes out to 5,000 wars. Crazy, ain't it?

As far as this topic goes, it's difficult to say, really. One would presume that other wars took place at some point, but the vast majority of Gaia's recorded history is unknown to the player.

I'd also like to point out that "magic," despite the fact that it is derivative from what can be called a naturally occurring energy force, has distinct and inarguable spiritual characteristics. While technological uses for Mako (which Shinra only brings about through an artificial process, although Mako can occur naturally) may continue to develop, "magic" itself is effectively immutable. The only real determining factors are one's knowledge/wisdom of the Lifestream, and one's Spirit Energy. Thus, while a natural explanation is given for "magic," it doesn't have to wholly conform to any sort of natural laws.

In TSW, spirit energy is used as a sustainable alternative to other energy forms, but it's unclear whether it's more efficient overall. Rather, I think it's the abundance and relative safety that made it the more popular choice. The movie mentions that the energy's generated from vats of micro-organisms; it's simply the 'energy of life' found in every living thing, much like the Lifestream in FFVII. Spirit energy is something with no equivalent in the science of our world; rather it's more akin to chi, or something similar - an invisible aura produced by anything that's alive. Rather than converting living matter into pure energy (like in a matter-antimatter annihilation), spirit energy can be extracted from living things (in the movie) or from its natural reserves in the Lifestream.
It's definitely at the core of FFVII's environmental message, since it nicely encompasses ideas such as sustainable energy, preservation of natural resources, and awareness of the dangers of radioactivity.

I don't have much to add here other than that Big D knows the score.