The only thing that keeps any number of parties from being competitive is certainly not the belief that voting for other than Republican, or Dumycrat is a wasted vote. There are so many other issues involved and what makes anyone think that a third party would be a panacea anyway?
There is plenty of examples of what happens when there are a plethora of equal political parties where none has a clear plurality of the citizenry. It is bad enough to have two sides to every issue; try dealing with a half dozen different views. Very few will ever be happy and the country is pulled in many different directions.
The system that has evolved in the United States is not unique; it just happens to be the most natural state of affairs. Human beans are not perfect, so why expect our politics to be perfect?
I think we have a very clear choice in the coming election--maybe as clear a choice as we've had in my lifetime. We have the capitalist against the communist, the somewhat conservative against the radical liberal, the flip flopper against the shameless liar . That seems like more than enough contrast to me. And don't forget, it was the primary voters who made these choices. That cannot be said of the third party candidates.