Frank,
My understanding is that because the 480's are so much younger, the money is better spent in keeping them operable.
The older K-37's, which have 1903 boilers, are also harder on trackwork.
In Durango, it has been hard to find money and time to restore K-28 #476 to operating condition, primarily because she is so much smaller.
So the C&TS and D&S are putting their money first into what gives the best and most profitable return.
But never give up the vibe.
As long as they are there, they can be restored.