The change (no pun intended) to a dollar coin has been a long time coming. Some of the reasons it has failed in the past are the failure to eliminate the dollar bill at the same time and the insistence on allowing the vending machine lobby too much input in the design.
The lobbyists want a coin that will fit existing machine slots, so we keep getting a coin the size of a quarter, which only confuses the public. The vending machine folks will simply have to do a re-fit; the coin needs to be clearly larger than a quarter. …