Ballina - hasn't happened yet but lets assume that sometime in the next 90 years - call it a 1 in 100 year event given we've gotten through the last 10 unscathed. At a cost of, say, $5m * 120 people plus a new airbus plus etc gets you close to $700m. What could you do at Ballina for $7m per year? Quite a bit I imagine. Extend the model to all similar airports in Oz and say its a 1 in 50 year incident and you have $14m/pa to spend across all similar airports. Going to pay for several new ATC positions plus increased radar coverage where required?
Unless Airservices are found to be liable, it won't be them paying out the $700m for a loss. Someone will pay - the insurers, and they will go after someone else to recoup their money. Ultimately, if AsA can deflect the blame, they won't pay. So they don't have and won't have $7m or $14m to throw around per annum. I would imagine that in the case of Airservices, unless they pay their own insurance premiums and are "privately" insured, the taxpayer is assuming the risk, (and saving the $7-14m per airport per year). The government will take that deal any day of the week.