BMW is free for new cars. Older BMWs, dealers charge up to $400 for an oil change depending on the model and the package the owner wants. Now, just like the Lexus you don't have to use the dealer so for the most part I agree with you.
As for Audis, why did the VW & Audi specific shop's owner I had my tires from TireRack installed at last year tell me never to trade my Lexus in on an Audi? He said that when he was doing research into which company to service with his new shop, VW & Audi were the clear choice because of their poor reliability and extreme dealer servicing cost which made the fact that their proprietary diagnostic equipment's 4 time higher cost worthwhile.
He had 5 Audis in the shop...all under 100,000 miles but out of warranty...every one had a $2k+ repair bill.