I would doubt that Ruxtell sold as many of the Model A units as they did for the T, due to the A's faster factory top-speed.... and the relative lack of high-speed roads during the Model A era.
I would hazard a guess that most of the Ruckstell Model-A four-speeds were purchased by owners living the flat mid and south-west... probably sold few if any here in hilly NE Pennsylvania.
When the V-8 was introduced, I imagine the speed-demons went for that rather than the four, and the market for the Ruckstell four-speed further diminished.
Chrysler offered a four-speed "double-high" transmission during the 1930-31 model years, but the option was dropped due to slow sales.