Back in the 50s, 60s and probably the 70s you could replace toaster heating elements, kettle elements and a whole host of other parts for appliances. Not today though, everything is throwaway. Metalurgy has been improved over the decades and is still being improved today. Back in the 70s, when the XS650 was being built, metals were terrible coming from Japan, aluminium castings were contaminated by all sorts of rubbish. Britain, famous for it's steels, did alright with steel, but their aluminium castings was never very good, porous, rough and that continued right into the 80s when the last 'real' Bonneville was made.
I did my time as a welder in the late 60s to early 70s, in the 60s steel was all Australian, but in the early 70s everyone started buying steel imported from Japan, terrible stuff, tube was twisted and there were all sorts of contaminants in it. It has improved since then though. Never owned a German bike or anything German for that matter, but their manufacturing processes are well known to be better than average.
Chinese? I don't have a problem with anything made in China, like any country's manufacturing, there are good and bad. I have Chinese $10 micrometers which measure exactly the same as my genuine Mitutoyo. My lathe, bandsaw, mill, belt sanders, pedestal drill, bench grinders and so on are all Chinese, never had a problem with any of them. I have a 4" Chinese angle grinder I bought nearly 20 years ago, despite being absolutely hammered it refuses to die. I can't say the same for several Makita power tools I binned, some only six months old.
Some Jeeps, the Vega, Pinto, dart, some mustangs, the Hornet, the Volare are all known for rusting. That's just American cars, there are plenty of British, Japanese, Australian and German cars that are all well known rust buckets.