Where are the 315/60/15 tires???

Does anyone know why tire companies seem to have stopped making 315/60/15 street or drag radials? Somehow, I remember BFG, Nitto, and Mickey Thompson all made street and drag radials in this size. Now it looks like MT ET streets R's are about the only option.

Is this just a function of tire manufacturers getting away from 15" tires???

Are there any remaining close alternatives to this size for a streetable drag radial?