Their official reason (for banning RCV) is that it is too confusing for voters.

So what do I know, I'm just a moron..?

...thanks for the great Reason/link.

Voters do find it confusing. Not all of them, but enough that it matters. E.g.: In San Francisco, Chesa Boudin only won as District Attorney in the final stage of the final vote count because his supporters were more likely to know about and use RCV than moderate, conservative, and/or low-information voters.

1. How much of that is due to its inherent complexity, and how much is just due to its novelty? If they had grown up in a society where RCV was the default, how many of those people would still have been confused?

2. People misunderstand that FPTP requires tactical voting as well; are the number of people who will continue to misunderstand RCV if it were to become common higher than the number of people who currently misunderstand FPTP?

Consider that anyone who suggests you to vote third party to "end the two-party system", before the voting system has changed, fundamentally misunderstands how FPTP works as well.