I think that on a properly maintened MB engine, the last thing in the car to go would be the engine, especially the bottom end. The bigger concern would be the accessories in the car such as A/C and accessories on the engine such as water pump, control systems, etc. I don't think that an engine with proper maintenance would suffer from internal mechanical failures too often.
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record