What the OP and others keep forgetting (or ignoring) is that should a "3rd party candidate" somehow get elected to the White House, the political machines of the "2 main parties" would go into overdrive to make him look as bad as possible...and his term would end with absolutely NOTHING accomplished. That might be the only time the D's and R's worked together with a common goal.
Then let them come together and shut us down, we'll do more. Plus he'd be the perfect President for our current fucked House and Senate, vetoing most everything. They'd have to work together if they wanted anything to get his signature first go around and not be made to look like complete idiots in front of the American people.