I don't know how much demand there is for royal blue, but I know people on the board have been looking for roual blue stretch Y gear for years.
Same thing with the first blackout a few years ago---the shirts were only sold in the week or so leading to the game and even then it was limited.
BYU approving more colors could lead to more demand. A guy can have only so many navy blue shirts. If BYU 3 or 4 options, I'd get all of them and I am not alone.