The American political duopoly is a result of our plurality (first past the post) election process. Third parties and independents are just not competitive with the two major parties and the duopoly passes legislation to keep it that way. Ranked choice voting is gaining popularity because it avoids the "spoiler effect" and the wasted vote detriment to "voting your conscience". There are other desirable voting methods such as STAR (score then automatic runoff) but they have not gained popularity. Any of them would be superior to plurality voting.