Power Duopolies are better than Power Monopolies but not by much and they certainly do not represent the true breadth of political beliefs of a population of millions of people.

In countries with such systems (at least in the ones I lived in) people get trained by the Press to expect everything boils down to “one side versus a the other side”, but if you actually analyse the whole thing and think about even simple choices in groups of people (say, “we’re should we go to next?” when out with friends) and it’s very rare that even for just one thing there are only 2 prefered choices in a group with more than 2 people, so now imagine how many possibilities there are in all combinations of preferences for all the social and political choices in a country of millions.

Representative Democracy by necessity is a heavilly reduced and simplified reflection of the preferences in the society they mean to represent and those variants of it where the representation system is Mathematically Rigged to de facto reduce that representation to just two, is literally the second farthest political system from properly representing a population, with the farthest one being dictatorship.

Personally I don’t count Power Duopolies like that real Democracies: a vote alone doesn’t make something a Democracy, otherwise Russia would be a Democracy. The again I grew up in a country with a lot more open Democracy (though still far from perfect) and lived for almost a decade in one with Proportional Vote.