15 years ago reverse-gravity casting was not used as routinely as it is now. It was used only for critical castings like rocker arms and aerospace products. That was just about the beginning of the transition.
I guess in the end I disagree with your tire people. That’s the “bottom line” of it.
alloy rims here in winter salty michigan get rim bead corrosion routinely. fill my wifes 2006 buick terazza tires weekly… all four tires. have the problem on two volvos 2000 and 2001 too. in fact it is expected here after ten years or so. the rim beads look like powdered doughnuts when you get the tires off. cant see how the casting process can prevent surface corrosion.