It's possible. Asmus made real leather jackets for their first 2 Aragorn figures if I remember correctly. I remember them posting an image with calipers showcasing how thin they managed to get it. As for color uniformity, they could (and probably would) dye the leather.Think about it,
1). Getting real leather at these thicknesses (1mm) isn't easy (believe me I've tried for custom stuff).
2). Colour uniformity. Natural leather has natural random colour. They need the colour to be the same here for 1000's of figures.
3). Cost
Plus how do you know there aren't the same or other issues with real leather at this thickness and size ?
I've found that it just depends. Sometimes just the leather looking part flakes off and the structure holds and other times it will all completely break apart like what happened with the DX05 Indy gun belt and bag strap.Its definitly doable its been proven lets face it the main reason they wont do it is number 3.
For people with experience with these belts do they completely crumble and disolve in the end or do they just flake but the structure holds at least?