I could make an argument that the conservatives could still be competitive in this alternate timeline, and would not necessarily need to fear the popular vote pact.
All they would need to do is change up their platform to capture more votes from outside their current demographic. But that might require them to stop being cartoon villains, and I'm not sure they're capable of taking their party back from the Trump ideology.
Let me happily inform you that several states have varying versions of RCV.
Maine and Alaska got there through a Democratic government and a voter referendum, respectively.
Highly recommend reading this Wikipedia page.
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.
This isn't a "both sides" thing.