I wondered the same thing prior to buying the car. However, I began to understand when I saw the route she had to take each day to work. Lots of stop/go stuff and holding on hills at stop lights, etc. Now, don't get me wrong, the replacements still tell me someone was riding a clutch, but ... don't really know, I never knew her.
Replacement records show charges of $5061.24 for the first replacement and $5037.67 for the second one - both done at the dealership. First one was negotiated under warranty, the second one was not.