1st Brigade(Stryker BCT) is in Ft Lewis and 4th BCT(ABN) is in Fort Richardson. The other brigades and smaller units in the 25th LID are in Schofield Barracks in Hawaii. I dunno where you got Kansas, etc from.
I assume the US Army wanted to have another Airborne unit, and have it based out west. So, they wanted the 25th ID(L) to have it, since they are the largest LID out west(AFAIK). Theres also the 172nd Infantry Brigade(Seperate) in Alaska, but obviously, you can't give them a Brigade, since thats the size of the unit, I think they have their own Airborne Battalion though.
Anyways, theres a lot(most/all?) of non Airborne Divisions with small Airborne units with in it, ie LRSDs, etc.