GM. Enginiggery. Put ferrous parts into the impossible to change position at corrosive environment.

could they just put a sacrificial high corrosion metal part on to eat the corrosion like they do in boats?

ngl, I would just scrape that rust off and then put a couple dozen coats of spray on because I don't know shit about construction stuff (If this is the wrong spray, yeah - would still use it. Zinc is what metal craves.)