I totally agree with all of the above statements, but as cars now basically have a lifespan of 5 years and not 35 or longer they are manufactured under the guise of "Fit for Purpose" which is what most manufacturers hide behind. Rest assured in 35 years no one will be thinking along these lines..................."I think I'm going to restore a ZB".
It's just not going to happen, nor will fossil fuel be around to operate the vehicle on as they'll all be electric by then. Australia is way behind in Electric vehicles opposed to Europe and it won't be long until we here in Australia will be "Forced" to make the change just like we were forced to accept music CD's when the record companies decided the only way to change people's buying habits of vinyl records was to simply stop making them.
Looking at the bigger picture and no I'm not a GM representative in any way, but the rust you are seeing on those components will not escalate to much more in our Australian conditions and thus will never affect the integrity of the componentry and what it's used for within the next 5 years.
In actual fact there are many Japanese made vehicles that had the exact same issues as depicted in the photo's above and many of those vehicles are still on the road being used daily 20 years later, just ask a 1997 Hilux owner who's pulled their instrument cluster out and had a look in behind there at all the bare steel bracketry, it's absolutely no different.