Partisanship is generally good,or at least not bad, in democracies.
Having two big-tent parties that shift platforms in search of a minimal winning coalition renders partisanship into empty tribalism, which is bad.
> people looooove a “bipartisan” bill
Bipartisan bills are the worst because they typically represent consensus of the (otherwise fragmented) elites against the people.
> but FPTP mathematically converges on a two party system, always.
FPTP creates structural incentives toward a two-party system, but voting behavior and party membership is not mathematically-determined behavior and thus no vote counting system “mathematically converges on” any party arrangement.
> To see this in effect, consider that a major party is incentivised to fund fringe opposition parties which will steal votes from the main rival.
And yet they rarely do; more often, and mor perniciously in practical effect, is that they are incentivized to negative campaigning since getting someone who would otherwise vote for the opposition to not vote is just as good as getting someone who is undecided to vote for you.
> There are many alternatives and RCV might not be your first choice, but make no mistake about it
IRV is very nearly the worst even semi-seriously advocated method that isn't FPTP (I won't call it RCV, since there are many ranked choice methods and IRV is worse than virtually all the rest.)
It is so little of an improvement over FPTP that I suspect the harm it would do to the entire idea of electoral reform through the disappointment it would produce in failing to fix the problems motivating a change in voting system would outweigh the very slight improvements it would produce.