"Stability" is not an absolute quantity. There are degrees of stability. A bike can be less stable at 180 than a Hayabusa and still be safe.
I have ridden many new bikes that get a little squirrelly at high speeds...head shake, frame flex, wheel wobble. Bike manufacturers have marketed plenty of bikes that are not perfect over 130 mph without ruining their reputation.
The Bus IS perfect. High speed stability is one of its defining features. But it is not reasonable to hold every bike built from now on to the standards set by the Hayabusa.
If the ZX12 or any other bike is somewhat less stable than the Busa, that does not make it "unmarketable."
If the 12 does not stop as quickly as a 996, does that make it "unmarketable?"
Kawasaki, and any other bike maker, is quite right to market a bike even though it is not as rock solid as a Busa at 180+.