Inch pitch chain looks a bit sturdier than a modern chain, the major problem is that they are unavailable. 1/8" width chain would probably be obsolete if it wasn't for BMX, and maybe track bikes. The sprockets are fairly hefty too, and the only time I've ever bent a sprocket is doing grinds on a BMX.
In my experience with old cars, it's only an issue with the stuff you haven't rebuilt and replaced, once everything is done they are reliable. I've had early 60's Vespa's that were a pain until the engine got rebuilt and all the cables were replaced then they were as reliable as a later P200e. Same with VWs, my most reliable one had it's original 36 hp, and once I replaced the generator with a remanufactured one I had a working charging system and bright lights. Still used the hand crank every once in a while for the heck of it. it could have benefitted from a later dual-acting master cylinder though.