Why? Wool can be darn effective, especially if we’re talking about springs and you’ve managed to find a ‘honey hole’ where they have stacked up.
To the OP, I’ve also found darker colors of wool (blue or green) to sometimes trigger springs though the peach/red range of colours would be my first thought too. Also Jensen eggs/gooeybob/corkies could be worth a shot. YMMV
I agree. It is unfortunate that flossers have chosen to use wool rather than beads or corkies. In the past couple seasons, it always takes me a day or two to re-lean just how small of a presentation you need when fishing with wool for springs. When submerged, the whole thing should poof out to no bigger than your thumbnail. Also, color really does seem to matter. Two years ago, it was peach, peach/red, or peach/white. Last year, it seemed like all they would bite was pink - bubble gum or hot pink.
Also, you want a short enough leader (18 to 24 inches) so you know your wool is down on the bottom where the fish are, and use enough lead to get it down there.
I fished a whole lot of roe last year, and only hooked one coho on it (and no springs).