And also it will be stupid for CA to get CX in *A, it's the best that you can get traffic from 2 alliance (ow + *A) instead of just one

If they need closer collaboration, they can just do joint venture flight (like HKG PEK). Imagine a CX flight to fly PEK then continue to MAN on CA callsign (CX metal), CX will quickly become the most popular one