Interesting post Patrick. But the Beetle is not flying through the air. It is in Ground Effect which makes a bit of a difference. Compare these 2 simulations.
And in ground effect.
When the Flow Illustrator site is back up, I'll make one of the ground effect shape in mid air and post it here too.
My point to this is that in ground effect, the air will tend to stay attached on more extreme shapes. Also, as Kamper Bob points out, if the air coming in from the sides has a smooth transition on a 3D shape, it will tend to help the air stay attached. Although I'm not clear on whether Bob thought it would help or hurt flow remaining attached.
But Again I say, this attached flow on an extreme shape is not our friend, it creates a lot of drag.