The JF-17 thunder is an export single seat fighter the program was launched to support Pakistan's need for Single Seat fighter plane , and joint research and development effort.
China did not needed the plane as much as Pakistan had a genuine need so that is why we received the TOT to break free from embargoes.
As for China why they have not depended only on JF17 thunder fighter plane is simple , China is developing 20-25 jet projects, so when they allocate their funding they allocate the funding based on large scheme of things
They are developing so many projects that they can't possible select all project that they develop
Let put it this way ...
Pakistan was thirsty , China was also thirsty
So Pakistan and China made a Lassi drink
Lassi is perfect for Pakistani with out meal but China , also made coca cola , they also got red wine , they also got Sprite and Rooh Afzah
So We are happy with Lassi , China can drink any drink they want -
But we are trying to also get our hands on J10B which is sorta like a better Lassi
Also point to note is that unlike Pakistan , China has already got HUGE inventory of planes , they can't shut them down , in moments notice and replace them ... budget concerns
But Pakistan is flying old Mirages from 70's so we are happy to replace our inventory - IMMEDIATELY
What did China Achieved from the Project :
a) Experience working with Pakistani Engineers on collaboration
b) They got a brand name fighter plane being used in World Top 10 airforce
c) They got to enhance Pakistan - China relations
d) Many customers have inquired about getting the planes
So what China gained was Trade (business benefits) what Pakistan got was Much needed Airforce over haul