I know a lot of people here don't 3D model (for a living, never mind a hobby), but a six month time frame for a set of armour seems right. You have to:
Make a basemesh (could take a day, could take 2 weeks - gotta make sure everything is clean and the polygons are organised a certain way) Sculpt (depends on level of detail, a good sculpt will never be quick though. Could take 1-2 weeks minimum) Retopologize (reorganize the mesh so you can lower the poly count while keep detail/density in areas that people look at and the areas that move a lot, could take a couple of days) UV Map (preparation for textures, depends on quality, but should take at least a couple of days for good work) Bake high poly to low poly (shouldn't take more than a day or two, depends on clean up and computer power) Texture (easier to texture when you have normal maps, but it still should take at least a week for all maps at a good quality)
That's just making the armour, then you gotta make sure it fits the character's movements and deforms correctly.
Binding and skinning (depends on complexity, but could take a few days).
Note: The above is for 1 character race/sex, not all.
If one guy is making a set of armour for all races, 6 months is fucking superman speed lol. I dunno how they organise their teams though, I doubt it's 1 person going through the whole pipeline at a company so large. My times are generous, during crunch you have to pack those days into hours. And it doesn't account for artistic standard, it just takes into consideration pure technical skill. The artsy side no doubt adds more time, including concepts and so on.