I meant to write they cant* undo it. They tried already but it didnt work, although there is a repeal effort that has survived some legal challeneges so it will be on the ballot in november, although i doubt it will pass
You'll notice a trend of Democrats and voter referendums driving RCV, and on the other hand, Republicans fighting to reverse or delay RCV laws, and entire conservative states that have BANNED it.
I'm aware of the progress, I am stating that I believe it to be a carrot that will get pulled away before it can actually make major impact on who controls the government.