In case you didn't notice when you were spending all this massive amount of time hanging around the MB shop, the 430 you spoke of is a V8. On the V8 you have two banks of cylinders, and many have four cams. This indeed requires a very lengthy chain with numerous sprockets, guides, etc. Most inline engines have a relatively short chain and quite a few less components.
MOST of the inline engines are much simpler in chain layout. Since the M103 engine, most of them have a ratcheting tensioner. A chain failure in the M103 is quite rare.
I am not an advocate of ignoring timing chains. I have replaced a few, which, when upon checking, showed to be "stretched". Notice I said, upon checking. It's not like there is no way to tell if a chain has worn. Are you aware that the chain stretch can be measured? A belt is a different thing, you can't really inspect it to see if it should be changed, thus there are recommended intervals for belt change, and rightfully so.
I also know from personal experience that chains in engine models with a decent chain life history, frequent oil changes will prevent timing chain "stretch".
I'm sure the salvage yards are full of engines with broken timing chains. The salvage yards are where the cars that never get the oil changed end up prematurely. Duh!! I wonder if I should change oil often?
Change oil hot and change oil often,