When a team is challenged evaluating talent, they are prone to overpay for just good talent. While they have improved, and I assume McClay is the reason for that because I don't think anyone in the family is anything but mediocre at it, they have not improved enough to be in the top echelon of the NFL.
The other issue is "good enough". Do you see anyone in that organization that is driven to excel on the field? Those that are driven are examining and evaluating their roster continuously to make improvement anywhere and everywhere they can with the only loyalty shown to a contract they cannot escape. However, as we saw with the HOU and Osweiler, there is always a way out if they seek it.
Look no further than how uncomfortable those in management and coaching might be for how motivated they are for improvement. Being comfortable in the NFL is the path to complacency. And that is the problem as I see it. There is no penalty to the Cowboys for cap mismanagement so it becomes a little too casual of a thought process. And the price to pay for success is one that the Jones family is unwilling to make.......stepping aside.