[greyface-]

Why, then, does approval voting continue to be so unpopular? It's much simpler than ranked choice or score voting, doesn't suffer from the failure modes described here, and elects candidates that satisfy a larger subset of voters than either FPTP or RCV - maximizing the consent of the governed.

[Maxatar]

Because the type of voting system to use ends up being subject to the same problem as the voting system it's trying to replace.

I live in Ontario, Canada, where there was a referendum on switching our voting system from first past the post. What ended up happening is that everyone starts to bicker over which specific voting system to switch to, proportional representation, run-off, this system, that system... so how do you vote for which alternative voting system to use?

While most people agree first past the post is a terrible system, not enough people are willing to unite to pick an alternative to replace it.

So approval voting probably is a fine system, but if you open the door to approval voting then you open the door to a host of other systems which act as spoilers and you're left with the status quo.

[greyface-]

Something similar happened in Seattle recently, too: https://ballotpedia.org/Seattle,_Washington,_Proposition_1A_...

It started with a referendum to switch several races from FPTP to approval. The (FPTP-elected) city council flipped out about this and proposed a RCV alternative, which triggered a vote between the two, and approval voting lost, thanks to a successful campaign that decried it as a "tech bro" "centrist" voting system that somehow produced worse outcomes than FPTP. It was baffling to watch these arguments succeed.