You haven't considered people who live off their credit card and have no "money" of their own. Regardless of how people choose to live their own financial lives, multi-charging is wrong and there is no way I can imagine that VA can't fix this if they wanted to. I just think they don't want to (or at least not in any great hurry) simply because they don't have to. They're making profits and filling planes so why fix what ain't broke? (in their eyes)
BTW, I'm not an Etihad customer so I don't know, but are they having these same issues with the Sabre migration?