Okay, I listened to the Shilao clip. It makes me think that the future of Russia/China joint projects in aerospace industry will be very hard to do. You get the impression that Russian aerospace industry still think of China as the China of 2005. If Russia continues to hold a dismissive view toward China, then no projects will be possible really. Given that Russia has had such a profound impact on China's aerospace industry, it's probably tough for the Russians to look at China as their equals in a project like this. I also don't see how Russia would be interested in buying aerospace equipment from China as long as they see Chinese aerospace industry as inferior to theirs.
I think it's important to note that while MS-21 seems to be a more advanced design than C919, a modern airline project is more than just the operational cost numbers. More important factors are the availability, reliability and maintainability of the aircraft. That's the side that A321NEO/737MAX has China and Russia crushed. Even, A220 has gotten the title of hangar queen from some people, because it's just not as available as A321NEO. And when we talk about maintenance and servicing, it's also about the suppliers. There is a reason C919 is going with many Western suppliers. They have well established international network and can service customers. It'd be hard for MS-21 or C919 to get orders outside of their home market without established suppliers. In China's case, it probably will need to have enough people sign up to C919 locally and build up local supplier network. Even then, the government will need to jump in and compensate the airlines when a domestic configured configured run into issues and the domestic supplier is having a hard time addressing it. That's why you see them doing these testing with Western suppliers. That's far and away the fastest way for C919 to get certified and delivered. Long term, they will probably develop domestic suppliers and sell them to various ministries or incentivize certain smaller domestic airlines to use them. There is really no other way to develop them, imo.