It was a problem here for the last couple of years. With the downturn in the lumber market, WRC was one of the few species you could make decent money on. So some mills (like the one down the road from me) switched to cedar exclusively. Other mills that had never handled it were suddenly cutting it. All of a sudden WRC was very hard to come by, especially for the little guy.
Of course all those mills saturated the market and prices fell. A couple of cedar-only mills have gone under recently. The one down the road lost its planer in a fire and is now shut down. So the supply situation is slowly improving in these parts.
Not that I really want to get into WRC.