At one time Bosch products had a bad reputation for failure. That may have gotten better, but I am not sure.
I've never heard of any such reputation for Bosch parts. They've always been well-respected for European cars. People bitch about certain parts in old cars but any electrical bit that is 25-35 years old is going to be sketchy, especially if it's in a car with 100,000+ miles and has experienced the weather and temperature fluctuations that cars do.
Responding to the question of how long plugs and wires are supposed to last, that depends entirely on the condition of the vehicle and how well it's maintained. If you're burning oil, if the mixture is off, if there's a head gasket leak, they'll die fast. If not, they'll last anywhere from 15,000 to 100,000 miles depending on the type of plug. Copper plugs in turbo engines only last about 15,000 miles, platinum plugs in low-stress engines can last 100,000 miles (my opinion is that they should be replaced every 50,000 miles but that's just me). If you have the wrong heat range of plug it can really throw that off as well.
Wire sets should last 50,000 to 100,000 miles, but that's again highly condition-dependent. If you keep the engine bay clean they'll last longer, if not, less long. If you don't route them through all the clips or if a clip is gone, they can vibrate against things in the engine and the insulation can abrade. Again, it all depends on the specific car.
ZV