Who would buy the 24-70 II when they could get something with the same focal range that's just as sharp, half the weight, more compact, and 2-3 stops more handholdable? Not many people. A few, but not many.
The 24-70 II is like the 70-200mm f/2.8 non-IS lens. Who buys that one?
If they can get the price of the 24-70mm f/4 IS down below $2,000, it's a sure winner.