Instant Runoff Voting (annoyingly called Ranked Choice Voting) has been proven by real world experience to suffer from Spoiler Effects and 2-Party Domination.
The annoying thing about it is that the entire field is very technical, not to mention actually convincing people that IRV is wrong. It is like trying to convince lay people of the difference between
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The one on the right killed over 100 people. And if we choose the technically (but for a relatively obscure reason) wrong voting method, it would lock in 2-party domination and make further actual reform much more difficult.
However, the voice of non-IRV reforms has been ignored, shut out, and locked up for so long that I am now officially a conspiracy theorist, against my own will.