Ford did consider doing it, however. They talked about using a fairly primitive setup, which would have involved using a chain to connect the engine to the tranny, but that idea was quickly squashed by the higher ups. (Henry Ford II was a pretty big jerk, from what I gather.)
My brother had a '67 Toronado with the cylindrical speedometer. When it was stopped (0), you could see the maximum speed of 135 below it. He tried to roll over the speedometer on a long straight road (in the Dakotas) and got to 128 until he came to a railroad crossing. When he saw sparks in the rear-view mirror he decided to slow down; that car was really low-slung. (And being so low, it wasn’t that great in deep snow.)
Hmmm; which sounds exactly like the system GM used. Would they have been infringing a GM patent, perhaps?