Voges was scoring big runs for years, his first class average is over 46, its just there were a hell of a lot of others ahead of him for Australia so he was unlucky. Now Australia have lost a lot of players he is finally getting a chance. You are comparing apples and oranges.
I am not completely sure a lot will depend on early season form if Hales scores big runs he might keep his place, Carberry (first class average over 42) looked far more suited to test cricket than Hales. Carberry played 5 tests against an on fire Johnson in Australia and then wasnt given another chance against a lesser team or weaker attack. I would also move Compton up to open before considering Hales. Then there is host of players who if they start the season well could be considered like Chopra at Warwickshire or Nick Browne at Essex. If Compton moved up then there are a lot of middle order players who could come in, Hilditch, Vince etc etc.