Well the fantasy to tech argument is normally made when discussing any fantasy work there are certain limitation, faux understanding, and suspensions of disbelieves. The examples given are specifically chosen because machines in general are not required for any of the materials in those examples. And while the trinkets are many that isn't really clashing with the gold encrusting of the existing cobalt armor, or the many pockets and satchels of the vanya robe.

The biggest thing that is required for organic growth of anything style included is accessibility and practicality. The Italian medieval>renaissance style was many layers of fabric and cuffs with elaborate patterns or very lively colors. Which differs greatly from the early Irish textiles because of climate, materials, and overall preference (That and Ireland didn't have an obsessive want for eastern fabrics like other european countries). Eorzea has been injected by Garlean influence that was morphing mass of ideas of other countries they have been absorbed into self. So more modern style can exist and while rose colored lenses aren't aviators I am sure the renaissance had their own sects of pop culture icon you can get today with the likes of Travis Touchdown.

Also this thread wasn't specifically meant to cover X, XIII, or any other specific game clothing just design ideas but the concepts where more readily available then say the concept art for the white SEED to show military uniform functionality, or pulling from early Enix or Squaresoft titles like Valkrye Profile or Chrono Trigger where concepts are mostly low res because when the artbooks were released or shots that don't give any specific detail other then specific icons. Lenneth helmet for instance is iconic and mimiced in many games with direct copies in RO, and Monster Hunter titles and Crono's blue gi is not much to write home about but it is no less a icon of him as his bright red hair.