I was also shocked at how quick my cable on my Ice Castle cables rusted. I changed them after 2 seasons out of concern
I then bought a Lodge, and had for 5 years before I sold and all 3 cables never got any rust what so ever.
You can buy certain stainless steel cables. I wonder if distinct builders (maker of the lodge would tell you what they use) Maybe ask if they’d sell you a set?
My bothers Ice castle is in the exact same condition, horribly rusty cables.