Just for clarification......
I have a friend who is a manager at the U.S. Mint. They have been trying for years to get US citizens to give up the dollar bill in favour of the dollar coin. It makes fiscal sense, obviously, since coins last longer than bills.
However, the U.S. Mint does not produce bills, those are produced by the U.S. Bureau of Engraving and Printing (USBEG) and issued by the US Federal Reserve Banks. It is the USBEG/Federal Reserve that is heavily influenced by the paper lobby and it is
that agency's responsibility to say "nope, sorry, the lowest demonination we'll issue is a $5.00 bill", not the Mint.
From wikipedia, which sums it up well:
"New notes printed to replace worn out notes (which have been withdrawn from circulation) bring in no net revenue to the government to offset the costs of printing new notes and destroying the old ones." Thus, the paper lobby benefits!
The Mint is one of the few US government agencies that actually makes money for the citizens (through the sale of collector's coins, proofs, etc) whilst the USBEG does not.