Any party that already has high likelihoods of winning the election will be hurt by RCV.
Your opposition to RCV should increase with your distance from the center. RCV reduces the chances of fringe candidates being successful. Traditional U.S. systems reduce the chances of centrists.
Most intelligent strategists prefer to lose 50% of elections than to lose 90% of elections.
No, it won't. RCV doesn’t hurt duopoly at all. It generally rewards the more centrist subfactions of whatever the two dominant factions would be without it, so if (in the USA) you views are best represented by a blend of the corporate capitalist neoliberal wing of the Democratic and the anti-Trump wing of the Republican Party, RCV is a boon for you.
If your views are not well represented in the current system, they will be even less represented with winner-take-all elections under RCV. For that, you need multiwinner elections producing proportional-ish results, whether party list, STV (the multiwinner system of which RCV/IRV is the single-winner form), MMP, or some other system.
Interestingly though (but not surprisingly) there is a lot of anti rank choice media coverage of the process.
When I tell people my city does that, some respond with “oh that sounds terrible! I heard the news that system is so complicated and hard to run! It probably took you weeks to find out who won!?”
This disconnect between my great experience with the system and the general perception of the process much bigger than I expected.
Now we just have to ask… who benefits from pushing a bad narrative about rank choice voting