[aggie]

Lack of independent thinking may indeed be a problem, but the reason for a two-party system is mostly due to the mechanics of our plurality voting system [1]. People don't vote for third parties because voting for the lesser evil with the best shot to win produces a better outcome than voting for true preferences that are likely to lose.

This problem of plurality mechanics could be largely addressed by instant runoff voting [2], which allows people to vote for their true preferences without fear of throwing their vote away. Of course the people in power don't want to make it harder to retain power, so getting something like this implemented is very difficult without a referendum.

This is just my speculation, but it seems that a two-party system removes most of the incentive for pursuing nuanced, independent thought. The depth of the decision you have to make is choosing one team or the other, and defaulting to their stances on most issues, or by a mix of resignation and cognitive dissonance, ignoring the areas of disagreement. And once you've made the decision for which team to be on (or inherited from your parents), it's usually set-it-and-forget-it.

[1] - https://en.wikipedia.org/wiki/Duverger%27s_law [2] - https://en.wikipedia.org/wiki/Instant-runoff_voting