They have to 'give it a go' so to speak and not rip it up mid-series. The problem is that those bowlers mentioned plus Harris and Pattinson (both injury-prone) have only played a handful of Tests between them. I think Bird has played a Test or two, Cummins has died and Starc is fairly new too. Faulkner is the other one I forgot about - another potential debutant. And their batting is a revolving door with mostly average players. Any progress they make in the bowling will be offset by poor batting. You'd think if there were many good batsmen coming through we'd have heard of them.