I had a mate used to run a fabrication shop, who's made me replacement bits in stainless for my BBQ amongst other bits, I guess it would cost more, but according to
ePer, the OEM one is about £140-odd (don't know if this is what you paid to replace) but if you knew it was sorted for life then probably worth paying a little more?
I'm hoping as mine was a bit scabby then it's been saved, if it goes later I can take it off to be sandblasted and refinished in POR15 or similar.
Hard to say what caused mine, it was gone on the rear and the 2 outer supports on front panel, also coating had blown on the inside too. Using a wallpaper screper, I was able to scrape great chunks of it off, and it was paper-thin.
Guess it's designed as a sacrificial part, hopefully you'd have some warning before it finally dropped off, can't imagine it rusting through the 2 most rear-ward mountings easily.
Mines being refitted tomorrow with new stainless fasteners with some copper grease.