They can't. It's either a cultural or ideological blindspot in china(and most oriental cultures) that they can improve upon existing technology but can't really create anything new. China sat on gunpowder for a thousand years barely using it for anything other than fireworks and some very limited military uses as signal rockets and rockets to scare enemy forces by firing them into the masses but they had no warheads. It never occured to the chinese all the other uses for explosives and when western traders brought it back to europe there was an explosion(har) of military and industrial uses that enabled a huge leap forward. That is how backwards dark age europe went from isolated villages and kinglets far behind china in most areas to quickly outpacing them and by the time the 1800's rolled along the west had ironclads and gatling guns and huge mechanized industry whilst the chinese where still mainly using swords and living like it was still the 7th century. Once the supply of new tech is shut off to china they will shrivel up and blow away as a global economic and military power.