And while automatic transmission will likely not last as long as the engine or the rest of the car, if an unusual amount of a certain model/year are coming in for transmission replacements with under 100,000 miles, IMO, there is indeed a problem beyond just wear and tear.

The only time I've known a transmission to fail under 100,000 miles as a result of just wear and tear, is if the fluid was never changed, it was abused (racing, etc.) or was used in heavy duty conditions (towing, heat, etc.)

Otherwise, there was usually a manufacturer defect. Wether or not the manufacturer (not naming any names, Ford) decides to do anything about it, is a different story.