That's actually a bit oversimplified for highly aerodynamic objects like aircraft. It is known that such shapes can approach (v)^2. A (v)^3 characteristic is more representative of shapes that actually do have to accelerate all the air up to the speed of the vehicle such as the proverbial flat plate.

This doesn't change the conclusion; you still end up with a low spot on the graph. It is just that the graph looks more like a parabola.