I agree with your tone, but sadly even in parliamentary systems with third and fourth parties like the UK and Canada, there is a strong bipolar two-party emphasis. And even worse the two parties that do capture power (in Canada the Liberals and Conservatives and in the UK Labour and the Conservatives) have themselves tended towards a rather homogeneous ideological mean, easily poaching policy from each other and rarely altering things that the previous party's gov't had enacted. A fairly standard neo-liberal consensus has settled over all western democracies that even the brutal crisis of 2008 couldn't shake, despite some rather horrible dysfunctions -- stagnant economic growth, growing wealth inequality, endemic poverty that doesn't go away, and a staggering slow moving long term environmental crisis that is going to make our children loathe us. Only in the periphery, in places like Greece, etc. have there been significant alterations to the political consensus, and that was quickly and efficiently snuffed out by the actions of the more "sensible" European mainstream...
In the end -- there's only one way of doing political-economy right now within the confines of western capitalist democracy. All the capital-P Politics is theatre around the margins.
What is really needed is genuine proportional representation, not FPTP (like in Britain). Another problem is that with three parties, voting for the third may siphon off votes from its nearest analogue (i.e. the NDP and Liberals in Canada under Harper).
In the end -- there's only one way of doing political-economy right now within the confines of western capitalist democracy. All the capital-P Politics is theatre around the margins.