/answers the call (late)

All magitek in Eorzea that wasn't built by Garlemald was designed by the Garlond Ironworks, and they can only build so much at a time. With so many chocobos (with which the economy is linked), I imagine the magitek mounts are low-priority for their team's R&D.

How many trains are running through Thanalan? At least one of the track systems belongs to the Empire and rolls right into their Thanalan castrum.