Because there are too many self-interest groups who have their own social and political agenda for whatever nefarious reasons rather than a collective effort and all pulling together in the same direction in the national interest. It could be done. Just hire a recently retired Army General, give him the money and the authority and it will happen. Make each 457 pilot visa $100,000 and channel that money into the training of locals to do the job. As a nation we will have to sacrifice those insane $29 and $69 airfares seen so often being advertised by Airlines and be prepared to pay more sensible airfares that will support the training of locals to fly the planes.
And if I can reflect on my experience working in the China pilot training pipeline for 3 years. I only ever saw one document or regulatory reference with a CAAC logo on it, and that was the Training Approval certificate mounted in a prominent position of the 2nd floor of Training Department. How many documents with a CASA logo on it does an individual need to navigate before they get a CPL?