As the until recently missing in action Captain Claret said, there were some in the country a few years ago, I can vouch for that seeing them first hand give demos at Avalon, I forget which year.
The one thing that blew me away sbout them was the size or the scoop for the water intake - about the size of a standard business envelope, one on each side.
I see to recall the fact that they don't drop just water. they mix a chemical fire retardant with it. If it's a canopy fire, they put more in to make the water coagulate in the treetops more, but if its a ground fire, they put less in to let the water mix drop through the canopy.
Chimbu hit the nail on the head with respect to the general lack of valuable land that is usually destroyed by fires. Fires as (property) destructive as this are seen every decade or so, and in the eyes of the government, probably aren't worth the cost in the long run.
We must also remember that the Australian bush will always burn, and the more we prevent it now, the more ferocious the fire will become when it does hit.
CS
PS - Chimbu, I sould suspect that there are many people who would take umbrage at your implication that its the National Parks people who light the fires...everyone knows it's the youth of today that do it.