With regard to the situation, I don't think Zynga gets nearly enough credit for its success. It is not that easy to copy software and get the same degree of success. Yet Zynga routinely copies and gets greater success. There is something there that deserves attention.
Zynga has operational chops that should not be underestimated. Whatever it is doing is cutting edge and enough of an advantage Zynga can even flourish doing nothing but blatantly derivative designs.
Eventually, those operational practices will spread to other game studios that do original designs and it will be harder for Zynga to do as well. But much like McDonalds, Zynga could enjoy its market superiority for a long time to come as long as it continues to innovate operationally even if it lags creatively.