玉 was a variant of 王 (king)[0] thus king in walls (国), it's definitely NOT "only jade".
Also isn't a land within borders still a better analogy for a country than a king within walls? Walls bounding a king seems more like a palace.
I think we have done exactly that[0], it's just not part of the 1986 proposal in PRC.
Why isn't "business" a measure of how busy you are?
Why isn't "waterboarding" analogous to "snowboarding" and "sandboarding"?
(As an engineer I hate these peculiarities and I'm all for fixing them but the majority of the world tends to want to stick to the not-necessarily-logical definitions.)