Actually, the mandate to appear on all state ballots is 5% popular vote, in previous election. A third party candidate, that doesn’t appear on ballots in every state, simply can’t win.
What electoral delegates represent 3rd parity in every state? In principle, we do not have a two party system. In practice, we do have a two party system. We just have a very steep barrier for 3rd parties, that makes the principal moot, to the effect.