It's always been that way although i think BA Gold used to be equal to CX Gold, at least for the regular flyers they keep track of. I always used to get bumped up until about 3 years ago when it suddenly stopped.
On regional flights PE is often undersold or not sold at all, but every man and his dog in HK is CX Silver or Gold so you'll be at the back of a long queue as a OWE.