It's not a matter of forecasting delays, it's a matter of how the costs and responsibilities are apportioned.
Hence why the
contract specifies if the delivery is more than 2 years late or the cost blows out by more than 25%, we can walk away without penalty.
Local production was non-negotiable, because creating an indigenous naval industry is actually more important than the subs themselves. There's no way that 90 billion dollar Naval Shipbuilding expenditure would meet broad public approval without the ramifications for local industry. That figure's also excluding the additional 50 billion expected to be required to maintain the submarines capabilities.
Australia is not chasing China on military spending or capabilities. The primary role of the Submarine fleet is deterrence.