Now Victoria has volunteered to host the major quarantine centre the other states shouldn't try to get one too. Its not an industry they want. Who wants the modern form of Leper Colony in their CBD?
Once this is built the most potentially dangerous and contagious passengers must be routed through there. For instance once it is built those flights coming from countries with the Delta Covid variant would have to go there rather into states only having hotel quarantine.
Who knows for how many years more Covid variants will evolve. There may be Ebola or other pandemics in future.