Tire cupping 2011 350 dually

[Batratbaseball]

I've got a 2011 F-350 dually crew cab long bed 4x4 with 26,400 miles and I need my 3rd set of tires.
The front and outer rears are cupping real bad. It's been to 3 Stealerships, 3
alignment shops, and 2 tire stores. Ford has finally told me its a truck characteristic. I spent $60,000 on a truck and just can't afford to buy tires twice a year @ $1200.00 a pop. Tire pressure is monitored weekly per the sticker in the door jamb. Alignment is better than factory, and nothing is bent, broken, loose, or missing in the suspension.
Any advice or experience with this situation please help a guy out. I've been a Ford guy since my Excursion in 2000, and this is my 3rd diesel. I have never had any issues with tires, so I'm lost. Please help!