I suspect that third parties are "crazy" precisely because they don't get much airtime. If they had TV time, there would be more incentive for the parties to promote remotely electable people (they'd still probably lose, but more because of the structural disadvantages that third parties are stuck with) because their candidates would have more of a chance to persuade people. (People who research information on their own are harder to persuade than people who just sit back and watch a debate.) But since that's not happening, third parties get dominated by ideological purists at best and crazy people at worst, which produces a self-perpetuating cycle.
This is because of game theory, not the media. If anything, the media gives third parties more attention than they deserve, and generally that attention involves someone famous with no shot at being on a major party ballot deciding to run in a third party because of ballot access issues.
Running in an election with the goal of making a decent showing simply isn't long term rational behavior in the US system. If real support is there, reasonable people seek to form a coalition with a chance of winning an election, and this is done usually within the major parties. Idealogues ignore rational behavior in the belief that if only the masses understood their party and its platform, their party would immediately become a player.
This is why third parties generally stink. Evangelical Christians organized and sold their support to the GOP for influence. Reasonable libertarians do the same, but since the idiotic LP siphons off some libertarian support the Xians have a stronger influence.
It isn't rational even before we note that a third party almost always takes votes away from the major party whose positions are closest to the third party's platform. This isn't essential as to the game theory analysis, but it adds a little bite to the assertion that third party politics is generally irrational.
There have been third party attempts for many, many years. None have succeeded, while the GOP did replace the Whigs, it was no longer a third party at that point. The Socialist Party did pretty good until the Democrats picked up organized labor as part of their coalition. In the modern era Democrats have let go of the southern white bloc as a means of attracting more progressive support from minorities and those concerned with civil rights. After a spattering third party spasm these groups were snapped up by the GOP as part of a Southern Strategy.
This is the only real purpose of a third party, a warning shot by a voting bloc that believes it isn't getting any value out of a coalition. If that bloc has enough support, one of the parties will change the platform in favor of that bloc, and the reasonable members will flee to the larger party which allows the chance of influencing policy, leaving the ninnies behind to scream in the wilderness.