One does not equal the other.
We are a two party system, and with some rare exceptions we have always been a two party system going back to the founding of our country. A lot of that has to do with how we hold our elections (winner take all) and the makeup of our legislative bodies (majority party control). If we had a parliamentary system, things would be different I suppose.
But just because we have a two party system does not mean you are required to vote for the "lesser of two evils". For one, the primary process gives people from all wings of the party the opportunity to compete for the ballot spot in the general election. Massie, Rand, Amash and others have all got to where they are today by competing in and winning primary contests. So the opportunities lie in the primaries. Then when the general election comes, if one is not pleased with the choices, they can abstain. Sure there may be minor party candidates on the ballot for emotional voters who need to "feel good" about their vote. But personally, with very rare exceptions (only one in recent memory) I prefer to abstain rather than vote for a minor party candidate, as I believe that my vote for them is an endorsement of their folly.