Why are eastern armors so cheap?

[Particle_Man]

Four mirror armour is like chain mail but cheaper; same for one of the lamellars vs. Breastplate. Why is this? This is looking at Ultimate Equipment.

[Fizban]

This was also a thing with Arms and Equipment Guide and Oriental Adventures in 3.x. Best I can think of is the writers just didn't care about a relation between cost and effect, assigned the stats similar or identical to a non-top tier armor that they thought was good enough to use, and wrote a low price because the armor is supposed to be a less advanced and thus less expensive design.

That said, PF does seem to have fixed the problem of maile just being bad, upping it to +6. The four-mirror armor is only slightly cheaper, and is also 5 lbs heavier. The "steel lamellar" with the same price is 5lbs lighter, however. Of course while they've fixed the lamellar problem of not specifying the band material, they've still failed to account for the level of coverage, so having iron (which should have little difference to steel in a style like lamellar or coat of plates [brigandine might be more annoying]) at +7 looks even weirder.

[Ashtagon]

It's a symptom of splatbooks. In order to sell the splat, they have to make the contents "better" than the core material.