I change oil around the 5-6K mark for my reasons but believe the extended life oil does work. BMW didn't trick us with their specification and recommended interval to weasel out of servicing the car free or not. Gas powered fleet services (cabs trucks) are using the same 15K marker and not sludging up or destroying engines.
It's hard to accept but is believable someone could run 130K on factory recommended intervals and have a tight engine. The VANOS issue is related to the seals not oil breaking down. Perhaps the "free maintenance program" was before LL rated synthetics were born?
Anything made can be made Better