Draenei are actually probably pretty close except on a vastly larger scale. Still I don't think they quite fit.

Note that one thing to take into consideration is technology in FF14 is built on magic ie. magitek. Its not going to operate the same as real world technology. There are also cultural trends that might have influenced things.

A few points though I'd make.

Dalamud was built at the very end of the Allag empire and its actual purpose was to siphon energy from the sun and channel it down into the Crystal Tower. Bahamut was as much a component as a prisoner as the Allag lacked the technology to build something that could handle channeling and manipulating that much Aether. Using an enslaved primal solved that shortfall.

Its also worth mentioning those roads survived a world wide earthquake that practically erased almost every other example of Allagan architecture from the surface of the world.