^^^
They tried several combinations, and all of them failed. Warner, Harris, Khawaja, Bancroft.etc were unable to perform on a consistent basis. IMO, they should drop all these four players and give chance to some young player.
They (Harris-27- and Bancroft-26-) looks pretty young to me, according to their Test career or if we go by the logic of age, Both are the product of Domestic cricket and performed well in the First Class. Age shouldn't matter much when selecting a team, but Merits Only and I agree that Cricket Boards should back the Young Guns if there are any. (Similar to Pritvi, Shubman, S.Curran,Matt Renshaw)
I don't remember the last time a teenager made international debut for Australia. Even Ricky Ponting was 20-years old when he made his test debut back in 1995. Their first class cricket is also aging, and the senior sides usually don't field any teenagers (on the other hand in India and England, you can find so many teenagers representing the domestic sides).
Guess you forgot Matt Renshaw. he was 20ish when he played his first Test Match for Australia.
Warner is 32 years old and Khawaja is also of the same age. I don't see a point in offering them a slot in the playing XI, at the cost of some younger player. Warner is essentially a T20/ODI player and including him in the test side can be justified only when there is no other option. Usman Khawaja has failed consistently during the last few years and his bating average is not what you may expect from someone who has played 44 tests for Australia.
With all due respect but you are half wrong and half right (Yes they are performing bad)
1. Warner average is 45ish in the test with 21 tons, even after performing bad. how many Test opener comes to your mind in recent time with this number?
2. Usman Khawaja average is 40ish in test and guess you forgot he made 750ish run in the last calendar year.
There are talented players available in Australia such as Matt Renshaw, Will Pucovski and Ben McDermott and the selectors should give them a chance.
Matt Renshaw is leading the list, but his recent performance in First Class is not good as Bancroft that's why Bancroft was the first choice for the Ashes.
Will Pucovski is very talented and promising young talent but still he doesn't have experience as an Opener even in the First Class Cricket and we are talking about International Games and Opening slot. CA can try him in Middle-order though but Wade's Century, M.Marsh's fifer deserve some chances too, Correct? And Paine is Test Captain.( that's pretty much Oz's Middle-order not even including no 3, 4 slot which is a fix for Smith /Marnus L)
Ben McDermott Same as above, plus not talented as Will Pucovski.