This is why I don’t think the dilemma is comparable:

However, in real life this is rarely how people judge how to cast their votes. Generally, Democrat and Republican voters are afraid to break rank because if the voters of one party vote 3rd party, and the voters in another part stick to party lines, this means that voters who voted 3rd party will end up with the short end of the stick. This incentivizes voters to stick to party lines and vote for candidates who are “good enough” (which represents the worst option of the prisoners dilemma in which both of the prisoners confess), reaffirming the two party system and preventing the possibility of more viable 3rd parties which can represent the views of the people better. source

Taking a thought experiment and scaling it for millions of voters is a fool’s errand. We’re dealing with social dynamics and fluid variables. I can agree that on an individual basis, or a small group, it could be a helpful tool. But, with large numbers it ceases to be viable. It fails to account for irrational prisoners that both confess, leading to the worst outcomes.