The problem is that:
(1) Once a player’s gear reaches a certain level, then there is too little good stuff to buy with MoFs on the Auction House.
(2) There are too few new players, who might need the stuff which is buyable for MoFs.
(3) There is still lots of good stuff to buy with Aurums, even for players with yellow and red gear.
(4) It is too easy to earn MoFs, if someone has lots of alts.
There is no easy way for Funcom to ‘fix’ this:
(1) They could come up with new attractive & rare items that are sellable for MoFs. This will be hard & require Dev resources.
(2) Attracting new players will be even harder, unless they spend lots of money overhauling the game engine, adding new content etc.
(3) If they make caches & other Aurum items less expensive, then they also reduce their dollar cash revenue.
(4) The easiest ‘fix’, from Funcom’s point of view, would be to reduce the supply of MoFs, for example, by reducing the amounts awarded by challenges. This will hurt players who only earn MoFs for own use, that is, to open dungeon chests & upgrade gear.
The other fixes suggested, such as capping Aurum sale price, won’t work and will just distort the market.
For example, if Aurum’s value is actually 250, but Funcom forces people to sell them at 200, then they’ll just stop selling, and now there’ll be an Aurum shortage and a ‘queue’ to buy it.
Funcom could also devalue Aurum, by creating new Aurum and selling it at a low price. This will hurt people who buy Aurums and reduce Funcom’s revenue.