From that link:
Even March may be too optimistic if they don't get the infection numbers down. Especially at a time of reaching high vaccination percentages.
Still, after February, they may not draw too many visitors since the weather starts to turn?
If I was asked to guess I'd say by March there will tourism. Probably not to every state and likely to only be initially from countries that are benchmarking to a certain daily case number. I think part of the ban is to do with logistics and optics. The federal government has an election coming and they are well behind in the polls. There are currently a limited number of flights into Australia and a lot of Australians who want to come home or go overseas to visit relatives (like me). Having headlines in the papers about Aussies being priced out of airline tickets by tourists will not to do the government any favours.