As long as the US keeps treating politics like it's a sport to be won by your team, and remain willfully ignorant of how big corporations actively run their country, it's not going to improve.
Even if you consider two-party system as failed multiparty one, it has advantage of being already past that bifurcation point. And, considering that alternative route is death of parliamentarianism, it's a nice advantage.
Yes, same failure can happen in two-party system, but chances are different - 'usurper' party has to fight against single opponent, rather than against multiple smaller ones. Question of 'whenever opposition can unite' is trivially true if opposition consists of single party.