The problem is we live under a system completely dominated by the interests of a single class, a dictatorship of capital, and the state reflects that. Under this system, any political party will ultimately be nothing than a mouthpiece for some faction of capitalists or a release valve for discontent with this system by subsuming revolutionary energy into impotent, declawed social movements. It doesn't matter if you have one party or eighty, you will never be allowed to vote away the economic hegemony, only fighting over social issues that do not threaten the stability of the system (not that these social issues aren't also important, but ultimately the investors that own the economy could care less if, say, gay marriage is legal so long as they can continue to own everything).

Movements towards things like ranked-choice voting, while not terrible ideas in of themselves, don't solve this problem. At best you'll get them but severely declawed to prop up the legitimacy of the state, and at worst they'll beat you down until you stop demanding even table scraps and accept that better things aren't possible. And even taking a lesser-evil approach to electoralism, like deciding that if you're going to live in a brutal imperialist shithole then you might as well live in one where gay people aren't hunted like dogs in the streets, inevitably reveals that the lesser evil rarely is as we've seen with the Democrats completely folding on anything even resembling a fight for reproductive rights or preventing LGBT pogroms while still continuing to support genocides the world over.