The AirBnB is already "taxed" when it's empty because the owner still has to pay rates, loan interest, body corp, etc. so they are already losing money if nobody is there. They would appear to be popular enough that that 'tax' is still a better deal than putting the place up for long term rent.
With the recent rule changes limiting rent increases but interest rates still so high, a short term rental is now probably more attractive to a property owner than a long term rental as far as covering the costs of owning the property.
If you want fewer AirBnBs and more rentals available, make it more attractive for property owners to provide long term rents, don't put them all off like they are doing now by making it such a hassle to make a place available for rent.
No argument there, BUT it's not just as simple as building more houses. It's no use building a bunch of affordable houses out at Toowoomba if all the jobs are still in Brisbane, as people still need to live near where they work. There are already plenty of affordable places to live, they are just too far for most people to commute. And nobody really likes the idea of knocking down houses close to Brisbane and replacing them with towering apartment blocks - the traffic is already bad enough as-is.
With more companies pushing for employees to come back to the office, I do wonder whether some sort of tax incentive to encourage remote work would be better. If a company received a financial incentive for each employee who lived more than 100 km from their base of operations, not only would that make it easier for people who cannot work remotely (e.g. peak hour traffic wouldn't be so bad) but it might help revitalise some of these country towns that are suffering from dwindling populations.