All it takes is a bunch of celebrities endorsing third parties and it's done. At some point in your lifetime you will probably see a third party winning in the usa and it will simply happen with media and celebrities redirecting everyone vote. It happens all the time in other countries: people get tired of the local rulers and to keep protests and disorder at bay the government through mass media redirects attentions to a new and fresh party that already got bribed and corrupted by the ruling class.