Brisbane could be a catalyst of real change for the Olympics and set a new standard of how a city can host it, and for the IOC that could mean renewed interest in cities wanting to host it which has fallen off a cliff. In fact that's why Brisbane was chosen to begin with, a 2nd tier world city without the profile or GDP of cities like Beijing, Tokyo or Paris, that would host it without spending gazillions.
If they build a 4B oval not only is it damaging the premier sporting code of the state and creating a huge hole in taxpayers wallet, but it even sets a dangerous precedent for the Olympics continuing the narrative that the IOC want to move away from, which is you need to spend billions on white elephant stadiums.