I used to make these costumes - not uniforms - as a hobby. I'd wear them to conventions, but usually just once or twice, certainly never got enough wear out of them to make the expense and number of hours involved worthwhile for any better reason than to do it. Like building ships in bottles or something.
Anyway, in some cases just duplicating the materials used in the screen-worn outfits was both difficult and very expensive. The TWOK uniform jackets, for instance - 100% wool elastique, about 19 oz, and the color had to be custom-dyed by a professional.
Here's a (bad cellphone) picture of a jacket I made about twenty years ago - it badly needs drycleaning and it certainly wouldn't fit me any more.