I think one of the reasons I'm a little surprised about Cathay not promoting these fares is that I'm certain that on the CX HK website about 2 years ago I saw these fares (not the actual prices, just the availability and rules) listed in their "Offers" section. When I went to have a look recently there is not one word mentioned about them. Particularly surprising considering the oneworld website tells us to check the websites of inidividual OW partners for details on the fares.

Yes you're right, they can't promote everything to everyone, but in the age of the internet-scouring-traveller, airline websites are one of the most effective marketing tools available to airlines, for very little marginal cost. You would think there would be some mention of these on the website.

As a comparison, on the QF website there is a section dedicated to the Oneworld explorer RTW fares, but nothing that I can find on the CX website. I suspect that maybe CX doesn't promote them due to the lower margins on these fares, but maybe it's just bad marketing.

To CX's credit, there is no mention of the circle pacific fares on the QF site.