My guess:
It was sold to the Kurdish organization in Northern Iraq, some terrorist groups, some dictators in Africa. I wouldn't even be surprised if it was sold to North Korea.
Capabilities that everyone knows. The plane has so many users that there will be no unknown capability left. This makes it easy to take precautions against it.
Kaan is important for this reason alone. Its capabilities may be less or more than the F-35, but the enemy will never be sure of this...