Thoughts on these disc brake rotors at 530k

[Texasdude74]

Buddy is freakin out after the highly skilled technicians at the Speedco in Brunswick, GA told him his rotors are all cracked on his '13 Pete 389 with 530k miles. He took the truck home and pulled all the tires off and this is what all ten rotors look like. He ordered ten new rotors at $297 each and ten sets of pads at $167 a set. None of the "cracks" can be felt with a finger nail nor do they seem to penetrate into the rotor. They look fine to me, I wouldn't worry about them at all and think those pads aren't even half used and I'd run them for another half million miles. He has more corrosion in the rotor vents than I would like to see, but his regular run is Jacksonville to Rhode Island so he sees a lot of salt in the winter. Anyone have much experience with the air disc setups?