The US Mint has tried pushing all kinds of dollar coins, and citizens just don’t want it.
If you can't easily tell a dollar coin from a 25¢ coin by feel alone it won't be accepted.
If they made a dollar coin the size of the old silver dollar coin and just pulled the paper dollars out of circulation people would accept it.
But the biggest impediment to replacing the paper dollar with a $1 coin is the vending machine industry. Millions and millions of vending machines would have to be modified or replaced so they could accept a $1 coin.
“citizens just don’t want it.”
If citizens were made aware of how filthy and germ/virus ridded singles were, they’d use the coins. I keep getting singles that have been disinfected, and make my wallet smell like cheap perfume. The metal in the coins is a natural germ killer. The coins can be recycled. Singles get shredded and are sent to a landfill. A huge, and dumb, waste of money printing them over and over. The coins last for decades at least! We need to stop spending money on everything we possibly can!