Someone posed the ponderafication of "why didn't they consider 'instant runoffs'?", with "they" being the folks trying to re-write the city charter. What's an "instant runoff" you ask? Well it is a scheme specifically designed to address the money and time costs of runoff elections while hewing true to the democratic notion that citizens have a right to vote. The system is quite simple. When you cast your ballot you select your first choice, then your second, then third and so on to n-1, where n is the number of options. When there is no candidate with a majority then the votes for the lowest vote-getter go to the candidate selected by the voter on their ballot. This iterates until a candidate achieves a majority. The winner may not be everyone's top choice but at least it isn't someone that a majority voted against.
So why didn't the folks trashing the charter go for this? Others have. The largest anti-rationalization is that it is complicated and not everyone will list a secondary or tertiary preference. So? Not voting is a voter's choice, just as valid as any other. Furthermore, taken to the extreme should all the electorate chose not to chose secondary candidates this scheme devolves to the "plurality wins" scheme the charter hackers recommend.
So that cannot be the real issue, can it? The real issue is as simple as it is obvious: partisan politics.
Democrats and Republicans are equally addicted to power and riches that control over government and politics affords them. They enjoy a duopoly they will not easily relinquish and will defend at all costs. Even if it means destruction of "little d" democracy as we're watching with the Charter Commission.
Instant runoffs are a threat to their power (and money) because it greatly increases the chances for third party candidates to gain office. Suppose an election offers these candidates: a Republican Right Wingnut; a Democratic Left Wingnut; and a third party candidate holding down the middle. With the current vote+runoff scheme few that might otherwise support the centrist will instead feel they must vote for the lesser of the two major party evils lest the greater of the two, in their opinion, win the election. In the current scheme a vote for a third party candidate is either a protest vote or a wasted vote. The plurality scheme further marginalizes third party candidates while increasing power of the incumbent party as any votes siphoned off by a third party candidate are likely to go to the party not currently holding the office. The current scheme limits third party viability, undermining democracy and the plurality scheme only makes it worse.
And the Democrats and Republicans who appointed the Charter Commission really, really like it that way.
This is despite the fact that instant runoff is not a guaranteed threat to the duopoly. Suppose the three aforementioned candidates are running for mayor with the Republican getting 40%, the Democrat 35% and the third party 25%. [Yes, the race is technically non-partisan but we all know who is waving what color flag.] With no clear majority the third party candidate is dropped and the votes re-counted with the third party supporters votes going to their second choice. As a result the winner will have a majority and in this example could in fact be the Democrat. Because THAT is the will of the people. Apparently NOT the will of the Commission.
Though not guaranteed, instant runoff is a very real threat to the duopoly. Suppose the same election is held with aforementioned bitter polarization of the main parties and that this acrimony is such that many True Blues and Red Bloods would really prefer another choice than their own party offers, but certainly not the other team's. With instant runoff, voting third party is no-harm no-foul as they can select their party's candidate as the second choice. It would also mean that staunch partisans can vote third party as their second choice denying the opposing party the win should their party not make the runoff. So if the numbers are Republican 40%, Democrat 25% and third party 35% it is possible, perhaps likely, that the third party candidate will take the win in the instant runoff. Is there any Republican or Democrat that wants to see THAT happen?