The point is that even tho you are logging to facebook, you are not paying them as much as those buying fords.
But we know that the auto industry is cut throat and low-margin. Paying $30K for a Ford doesn't mean Ford just made $30K. Between manufacturing, R&D, marketing, and raw customer acquisition cost (dealerships aren't free), I'd be surprised if Ford walked away with 5% of that.
That's why the author specifically mentions profit, which Ford has 8x more than Facebook.