With the widespread coverage of bipartisan politics, there seems to be no room for publicity of minority parties. Voters with minority views may not vote for their party because they see it as a "wasted vote" and instead go for whichever of the big two happens to be closer to, but not quite like their views. Potential candidates from these parties often have to relabel themselves as either Dem or Rep to even hope for a spot in the Primaries. Most people don't even know that we HAVE other parties who can nominate Presidential candidates.
A third party presidential candidate may not make it in the final election, but their presence in the debate -being able to answer for their ideologies- may inspire potential congressmen to join these parties and bring new ideas into our gridlocked system.