Modern vs Medieval, what time is it?

[Edax]

I think that the presence of magic REALLY skews things a lot. I suspect it's a lot more pervasive than we might think, which could explain why spears and bows are a match for firearms.

Actually that comes down to metallurgy, if bullets cannot penetrate mythril or other fantasy metals, then melee weapons and heavy armor remain practical. Part of the Armorsmithing quest involves making a set of chainmail bulletproof.

While Garlean technology DOES give them an advantage, the advantage should be OVERWHELMING, but the game presents it as just an edge.

I get the impression that Garlean technology is hugely wasteful of raw resources. Whatever advantages in combat they offer seems to be offset by just how much material went into their production. When I look at their bases they just seem so hugely wasteful in metal. The Garleans build a giant artillery cannon and instead of using it to bombard Eorzea from their side of the wall, they instead use it to blow up their own buildings and shoot at their own men thanks to Zenos.