Actually Cathay have a very strong relationship with Finnair and pass a lot of connecting traffic through Helsinki to westbound destinations they do not serve themselves.
Perhaps Qatar’s methods are more a reflection of the meglomaniac who runs it and his ambitions rather than anything to do with Oneworld.
The Qantas/Emirates relationship was long established when QR joined Oneworld and it is time limited if not renewed. That said QF seem to find it highly beneficial and it has certainly improved their performance.
I’ve said before, the alliances have run their course and they are too big. I’ve also said Etihad seem to have the right way forward and that is now being copied. It will take the members who are at the core of alliances e.g. LH a long time to wake up to this and some no doubt will be too late to the table.