I'm glad you asked. The reason why Toyota et al closed their doors was because it was impossible to build a competitive vehicle in this country because of labour costs etc.
So indeed the closure was inevitable. The outcry at the time was that we would have mass unemployment in the sector and closures of small to medium industries that supply parts.
Instead there was no spike and the transition was measured and successful.
https://www.smh.com.au/business/the...akers-closed-their-doors-20190613-p51xdl.html
Indeed it was a perfect case study of how workers in a redundant industry can retool and gain alternative employment. Which makes the paranoid protectionism of the coal jobs by LNP factions ridiculous.