The two party system is the system we have because we believe in the efficacy of it.

No, noone believes in the efficacy of it. It is the system you have because it is now beyond anyone’s powers to reform it. It is a mixture of archaic and wilfully corrupt laws and rules, which has petrified into something that disproportionally serves one minority fringe and its interests over all others.

The majority of people does not think it serves their interests, but they are powerless to change it exactly because the small but powerful group whom it actually benefits has disproportionate power to prevent it from happening.