The History Goes Back Further Than That
El Reg said: "Launched in 2016, Phoenix was an IBM implementation of the Oracle PeopleSoft platform"
It was actually started well before then, in 2009, under the previous government. The contract was awarded to IBM in 2011. It was part of an overhaul of IT systems which were consolidated as a "cost saving" measure. It went live just as the present government came to power after the election.
None of the other projects which were initiated as part of this cost saving project were successful either. It became obvious soon after it went live that the project was in trouble. The opposition are of course blaming the government for not having pulled the plug on it immediately after being elected.
The Auditor General's investigation didn't really address whether IBM did a good job or not. Rather it focused on whether the government's response to things going wrong was adequate.
From what I can see, the major problem was that the project was rammed through, ready or not, prior to the election in order to claim the cost savings for electoral campaign purposes, and there was no "plan B" if "plan A" didn't come off perfectly.
It turned out though that payroll for such a broad range of employees was much more complicated than had been envisioned back when the project was started nearly a decade ago.
The main failing of the present government has been in persisting in trying to salvage something from the mess they inherited instead of pulling the plug on it earlier. Their response to that however is that there was no fall back position available. The Auditor General however noted that the government of Queensland had pulled the plug much sooner when they faced a similar problem.
The project which was supposed to save $70 million per year has turned into a persistent financial black hole which will continue to cost money for years to come.