They couldn't get the public to accept them because they were too close to the quarter in size or were too bulky to carry around.

Chicago Tribune:

The U.S. government, its vaults stuffed with 1.4 billion one-dollar coins bearing the likenesses of dead presidents, has had enough of them. It is going to curtail production.

"Nobody wants them," Vice President Joe Biden said Tuesday. That is for sure: The Mint says there are enough $1 coins sitting in Federal Reserve vaults to meet demand for a decade, and the inventory was on track to hit two billion by 2016.

More than 40 percent of the coins that are minted are returned to the government unwanted, the Treasury said. The rest apparently sit in vending machines -- one of the few places they are widely used -- or in the drawers of coin collectors.

What the coins don't do is get around much. In fact, the Mint has never had much luck with dollar coins. The Susan B. Anthony dollar (1979-1981, revived for one year in 1999) never caught on; some people said it was too close in size to the quarter. Neither did the Sacagawea Golden Dollars (2000-2008) or its successor, the Native American $1 Coin, which has the same front but a different back.

In fact, about the only supportes of the coins were the vending machine industry, which saw great potential in building new machines to handle more expensive products. But now that dollar acceptor technology has been vastly improved, the coins don't even have much backing among the vending machine lobby.

Another example of government trying to foist something on the American people that was roundly rejected.