If apprentice numbers are down 40% in a decade, this would be because apprenticeships are not available in the numbers they were previously. I doubt there is a vacancy offered for an apprentice that is not filled. The reasons for the decline in apprenticeships available is something that obviously needs drastic attention. I'm pretty sure that any more university places made available for future professionals to study would also be quickly filled although the course requirements and costs might need tweaking.
Our national skills deficit gets worse because we do not do enough to train the young up and comers who are already here but instead take the short term fix and import workers. Skilled migration should be used to fill unexpected shortcomings, not as the norm. We had a mining boom and the level of tradesmen, engineers and the like could not reasonably have been foreseen so we sought skilled migrants. At the same time, we should have seen a huge ramp up of training of Australian youth. These newly skilled people should now be in our workforce and so the need for skilled migration should be almost zero in the current economic climate but is it?