Originally Posted by Airhead Wrangler
It's because those same parts were probably used on 15 different models. Hell, they might still be using them on current models. The 'parts guys' around here can speak to it better than I can, but there are a good number of parts that were used on a whole range of models spanning multiple decades. Those germans got as much mileage as they could out of a lot of things. Swingarm pivot pins come to mind. Driveshaft boots. Final drive bearings and shims. The same huge custom final drive bearing was used in BMW final drives from 1981 until 2005. I'm sure there are other even more extreme examples.
The front wheel bearings for a 53 Porsche are the same part number as at least late 80's 911's.