Because as popular as the Mirage 2000 is, France/Dassault, in their infinite wisdom, shut production down early despite the still significant interest in the very capable plane. Brazil, India and several other nations would have selected them for their future needs. In fact, I do recall reading several statements over the past few years where the Indians have said they would have preferred the Mirage 2000-5 for it's MCA tender. For anyone wanting Mirages now, they have to buy them second hand all because it was considered a threat to Rafale sales. I think France/Dassault didn't just shoot themselves in the foot, they blew it clean off with this blunder and cost themselves significant future sales.
Then again, given the nature of the Air Support/Air policing roles, the JF-17 would fit that role very nicely. Still, of China's exports, I think it's got nothing on that sweet J-10!