If a "third" party had a complete platform on every issue just like the main two parties, then that party would have more of a chance of attracting a major following.there is definitely an effort to keep all third parties off the ballot and out of power.
But, none of them do.
They are all limited reactions to one or two planks they didn't like in one of the two major parties from which they defected ... and thus they understandably simply have a limited following.
Also ... once the dualism forms (Republicans v. Democrats, conservatives v. liberals, men v. women, young v. old, etc.) the magnetism of such alignments is difficult to degouse.
When a truly complete party, one that balances both security and freedom dynamically, that respects the foundational right to life, and that advocates true progress without surrendering the good we now have ... then you will see that "third" party actually take over from the other two.
With regard to libertarianism, it is merely based on the dysfunction of indiviualism and a worship of the Money System at the expense of societal ethics and morality.
Because we are moving away from dysfunction and toward health, such a political philosophy is extinctly headed in Barney's direction.