"If WB is marginal for Chinook why are they trying to have wild Chinook at all?"

I think the stated reason is that WDFW was concerned that continuing to manage WB as a Chinook hatchery wipe out fishery could lead to NMFS listing WB "wild" Chinook under the ESA. And this led to some urgency to develop a manufactured population of naturally self-sustaining wild WB Chinook.

I bet a dollar to a doughnut hole that it isn't possible in the Willapa River in the forthcoming half century.