The Chinese government have nothing to lose neither do bitcoin but the people of course especially does who are pro-bitcoin and enthusiasts and including those who have ventured heavily into bitcoin mining, the investors who have held since they one and those who operate as exchange locally as a merchant and globally. However, they can still move out to countries that welcome bitcoin and its investors.
If one day bitcoin gets accepted y half of the world, China is just like the US that is opportunist, they will want to have their hands in bitcoin heavily to control and know what is happening in the decentralized ecosystem and it might be too late by that time. Any country that bans bitcoin will just do fine aside from their people that may be affected by not been able to have one.