Shortage of Cabs caused by shortage of drivers. With the current good economic conditions there are plenty of unskilled/semi skilled jobs around paying +/-$20/hour plus superannuation ,sick pay ,holiday pay ,workers comp ,regular working hours etc.
Why would anyone drive a cab for +/-$12/hour , with no other benefits what so ever , working 60 hours a week including nights weekends and public holidays ? Not to mention the risks
Even if you had found a taxi the driver would probably have been unable to speak English or even know the way into the city ,as the only people who are willing to accept the working conditions are very recent arrivals or those who cannot get any other job.
Taxi fares are simply too low to provide a decent service.