Obsessed, I can only offer theory on that.
My best guess is that presently C&R is only hope for wild steelhead fisheries at all. In most places there is no risk of a forgone opportunity issue because they are lucky if they even make escapement goals. Thats why you never even hear it brought up except on the peninsula.
Alot of it is the politics of it. When you have very few fish state wide, the only people fishing are the dedicated anglers. The majority of the dedicated steelhead anglers want to fish regardless if you can keep them or not so you see a large C&R push. Now if the runs were to recover, you would see many more of the less dedicated get back into angling again. The less dedicated don't care about C&R, they want dinner. Then you would see the percentage of anglers who want kill fisheries go up and with so many fish, it would be tough to justify C&R.
Thats why I agree with most of you that the only real fix is a philosophy change. While I support C&R I realize its only a band-aid fix. It in no way guarentees more fish to the spawning grounds. I can not remember the exact wording from the court documents but I remember that the language specificly said harvest. It was something like "if one party is unable to harvest their half of the fish, the other party may choose to harvest them". The other part of the rulings that was interesting was the part specificly talking about how the tribal share could be seasonal. The judge (I think it was still Boldt at this point) even went so far to recomend that the tribes take their half from the winter run and leave the summer mostly alone (where applicable). I am not sure of his reasoning on that though, except that more anglers would rather fish when its warm out.
The bottom line is that the only way to change the ruling is to back to court (much $$$, and no guarentee) or loby US congress. An act of congress is an automatic treaty modification.