Because China wants to be able to manufacture everything so that they are beholden to no one. Seize the means of production as it were.
Most of China's innovations in aircraft stem from the fact that they lack the advanced metallurgy and engine manufacturing chops to make powerful engines. Their equivalent to the Blackhawk helicopter uses an advanced fly-by-wire system instead of heavy hydraulics systems because they can't produce an engine powerful enough to meet operational requirements and have hydraulic controls.
Most of China's innovations in aircraft stem from the fact that they lack the advanced metallurgy and engine manufacturing chops to make powerful engines. Their equivalent to the Blackhawk helicopter uses an advanced fly-by-wire system instead of heavy hydraulics systems because they can't produce an engine powerful enough to meet operational requirements and have hydraulic controls.