Oh, come on now. The old planes are in Arizona because they are no longer economical to fix and/or fly. You can fix a plane almost indefinately. Just replace the parts that are fatigued and or broken.
First of all, these planes used in slurry drops are not, and never were passenger aircraft. They were military bombers. They were designed, from the ground up, to carry heavy loads and to be able to drop those loads quickly. Why are they using such old aircraft? Simple...there are no new aircraft of that type available on the civilian market! Think about it. The B-52 that the Air Force is still flying....is a 1950's era aircraft. They are still on active duty...not available for sale to civilians. Next comes the B-1 type aircraft and fighter-bombers.
All of the pure bomber aircraft, those specifically designed for similar type of service as slurry bombers, other than the B-1 or B-2 "latest and greatest" are 50 years old or more.
The way many in the media is portraying this is that Hawkins and Powers cut back on maintenance to make money. Wrong...how much money do you think they're making now??? Do you think this was a "wanted" outcome? That though is just as ludicrous as saying the pilots *purposefully* overstressed the aircraft to make the wings fall off to prove the aircraft was unsafe.
Hawkins and Powers maintained those aircraft as well as they could (certainly within FAA regulations) and the pilots were experienced well trained personnel. Accidents happen, it's too bad...but they DO happen.
Quit trying to blame "someone, anyone!" for an accident...."stuff happens" it really does!