I recall similar scenes after opening up old Jaguar XJ6 engines due for an overhaul in the 80's.

My second car, a '85 Peugeot 505 GTi gets its oil changed every 10,000 km or 6 months. I use normal 20W/50 multi-grade, not synthetic. I've now done over 240,000 km and when setting the tappets everything still looks as good as new. I did the head gasket at 180,000 and could still clearly see the honing marks.

I think I'll take my 540i's tappet cover off one of these days just for a look. Maybe I should follow the same 10,000km/6 months routine. At the last oil change I was advised not to use a fully synthetic as this was apparently too thin for such an old engine.