Right now most movies are sold an physical data carriers. Sure, bandwidth increases but so does file size. Streaming a blue ray disc probably isn't fun.
With a car or other physical products the person getting it used is getting a worse product than the person who got it new, adding incentive to buy new. No such thing exists with media.
And then again we don't quite know yet how long photo-optical storage will last, but it probably won't last forever.
But the point you're actually missing here is exclusiveness in consumption. As long as those 20 people are not playing Bioshock at the same time the developer is no more entitled to their money than the car manufacturer is in you example. They sold one copy of the game and one person is playing it. That's the end of the deal for the developer.