The last two attempts were failures because The People didnt want them. The People, or the banks and retailers? There are few banks and credit unions even carrying them anymore, but I often overhear customers asking for them. Of course, the customers are just ordinary people, not major retailers with large accounts.
I prefer the dollar coins. A buck wont buy much these days, and pulling my wallet out for a dollar purchase is a bit more hassle than its worth. A dollar is pocket change and it should be a coin.
I guess no one remembers Worthless as a Missouri Mill. These were aluminum coins about the size of a nickle, and had a hole in the center. We used them as washers frequently. I seem to remember hard pressed paper mills as well.