OK - let's concentrate on MEL-PER-MEL.
QF9 - leaves Melbourne at 16:15 (AEDT) arrives Perth 17:15. Need to be at MEL T2 at least 15:15 - pretty much rules out most business passengers as, with the trip from the CBD you lose most of the afternoon. No chance of inflight wi-fi - another negative for business passengers travelling in Y (yes, we *do* exist!!). Stricter constraints on LAGs ... not really an issue for most experienced travellers, no different to jumping the ditch.
For the leisure traveller who is probably more price conscious, Tiger, JQ and VA all tend to come in cheaper ...
QF10 - leaves PER at 13:25 and arrives in to MEL at 19:55 (AEDT). Again, you've knocked out half of a business day. Again, for the leisure traveller, QF prices well ahead of the competitors.
My guess is that should QF establish a B787 hub at PER the domestic legs would disappear.
Regards,
BD