Why does JCPenney not carry dimes?

A friend of mine from college used to be in management at a JC Penny's. She told me that the reason why is that JC Penny didn't see the reason why there was such a coin as a dime.

His reasoning was:

If 5 pennies make a nickle, and

5 nickles make a quarter, and

4 quarters make a dollar...

Then what purpose does a coin have that's only a multiple of two of the next smallest piece of currency, i.e. 2 nickles make a dime?

I know that when I worked in retail, even before I learned this tidbit, I would go to great lengths to keep from opening up a roll of dimes in my register. They were a pain in the backside to count. Once the unrolled dimes in my till were used up, I would give two nickles instead of one dime.