XA-XD commercials were far worst for rust than HQ-WB. That (and the way the Holden was constructed) is the reason why there is so many more Holden commercials left today. The XA-XD commercials rusted out in the sills/floors very early in life and it was structural hence they were taken off the road and wrecked/scrapped - or they were used in demolition derbies as they are a monocoque construction (and got flattended by HR-HG's). Normal rust in a HQ-WB commercial is superficial and easily repaired ie cowls and floors. Or the cars were easily rebodied in half a day with a few mates - there used to be heaps of tradies utes around local to me even less than 10 years ago with mismatching panels and colours. All that era Fords were gone as trade vehicles by the 90's. I'm not sure what Ford did by the time XF came around as they seemed to have lasted better yet they are identical construction. Maybe zinc coated steel like the 62 series 'cruisers?
I remember my cousin buying an XC ute in the very early 80's, it was only 3-4 years old and had been all its life in Tamworth area. It had bad rust in the sills even then, rest of the car was schmick.