You know, I thought the same thing. Steve doesn't drive a BMW. But I'm almost 100% sure his example in the talk was BMW. I can only guess that it was because BMW market share (which was sub-2%) fit the example, since that was Apple's market share at the time.
Steve owned at least 1 BMW in the last 10 years that I know of specifically.
The famous footage of him riding his motorcycle was, I think, a BMW motorcycle.