That sentiment is super popular, but I haven't had much of a slow down. Lightning Jack and Bay Bee Cottontail are the official anthem of newbie coyote callers, but they do still work, just as well around here as they always have, when used well.
Get away from the E-caller, and every hunter sounds different. I did as well this winter with a Doug McCarty Ironstone Custom acrylic open reed distress and a Kerry Carver Swift closed reed as I always have.