Personally I do not think Greenie and Buckingham are better coaches (as a tandem) than Ernie Merrick. Yet we did not play much worse under their leadership after Ernie left, than under Ernie's leadership (in the "late Ernie period"). This does not mean Des and Green are just as good as Ernie and that they would win the A-League title with Victory or the Jets. it simply means the opposite: that the Ernie- (or Herbert- in his final season) -coached WPX simply could not compete with other teams successfully. But we did compete, earlier on.
I have no ready answers. But it could be that prudent fiscal management, and paying our players on time, leaves us with a budget that does not leave room for better players - such as other teams can have right now? I may be completely wrong here, because of the capped salaries.
What is the financial situation of other teams, are they buying better performance on the field with borrowed / fake / money?