American voters in both major parties consistently vote against their own collective interests in order to maximize individual gain.

Well said, but it’s not just American voters. Also it depends very much on how you explain things to voters - individual gain and collective interest are not opposites, but that’s what a corporate lobbyism/propaganda machine has been promoting for many decades.

For example, consider that the historical self-narrative and cultural lexicon for young American students is essentially:

Yeah just yesterday I watched snippets of old Reagan & Bush II speeches. They are so dumb and smarmy and naive.