Except people don’t vote for the President. The electorates do. Which is a fancy way of saying that Congress does. As long as Democrats and Republicans dominate over third party and independent electorates, we will never have a third party candidate.
Supposedly, even if a third party candidate won by a landslide in the popular vote with a record voter turnout, the electorate doesn’t have to consider that candidate as viable and still select only the Republican or Democrat candidate with the highest vote of just those two parties.
The only way we can have a third party candidate win in an election is if a single third party overtook the house or senate. But third parties are only recognized as independent and they end up cozying up to either one party or the the other depending on which ones hold majority or share similar interests. So, even then, it’s so unlikely that’s it’s next to impossible.
Not without a significant overhaul of how our congress has operated in the last 150 years.