Would you mind sharing some evidence? To the best of my knowledge, China has sent their AF aerobatic team, which is consisted of the J-10A’s, abroad many times for demonstration purposes. I have not heard anything about China attempting to market their J-10 to other countries. Many have expressed interest, but China has not shown their willingness to sell.
Here is reliable Source. Iran wanted to buy J-10 with local production capability. China wanted oil & gas in return of fighter jet. I believe Iranian delegates visited China to discuss strengthening military ties with China other than fighter jet procurement.
Former Pakistani prime minister visited China and discussed J-10 procurement.
Bangladesh and Argentina cannot afford to buy fighter jet until China offers some loan forgiveness. Bangladesh and Argentina do not have manpower and infrastructure to maintain such fighter jet unless China lend their manpower. For example Chinese defense contractor and military advisor help Bangladesh operates type 35G submarine because Bangladesh has no clue what are they doing?
I can only assume Engine is the only component of J-10 which is holding back China to flood the market with J-10.
Why am I optimistic? Simply because China flooded the market with Type 056 Corvette and OPV because of mass production capabilities of China. Ship building might of China is now in global scale.
There are many goodies regarding J-10C and there are many unknown which we don't know. Maybe Industrial secrets such as Engines capability. Maybe that's why China is working closely with Ukrainian and Russian, maintaining a delicate relationship between both.
Second reason, again I am assuming...
China is only country in the world with too many fighter jet programs, training aircraft programs, UAS and UAV programs. It takes hundreds of thousands of skilled manpower and monetary commitment to protect massive investment.
You may add more to these two.