Or simply they cannot fix it, because they try it in the wrong way - like with Cyrrodil - I am convinced that the solution would have to be a change in the combat mechanics in order to end zerging and AoE spam - but they do not address that and so there is no progress with performance - at least not in an amount as required. They try to remedy symptoms instead to cure the disease, which is the horrible game mechanic, which makes zergs and AoE spam desirable for far too many players.