The rate is $200,000 per day, I believe. The private owners invested 50 million in the conversion, and need to recoup the investment. There is also an enormous operating cost. It is apparently worth the cost if you need a big patch of ground covered quickly with fire retardant..
Report: U.S.-led strikes in Iraq, Syria killed 459 civilians (AP)
from the article: Firefighters subdue Carmel fire after 77-hour blaze