@ChrisMayLA6 I do not have the answer. If I were to speculate lobbyism is one factor crushing it, in some cases the ideology is too extreme and it is justified that it remains small, a compromising culture (in northern europe) sees compromising as "adult" and something to strive after, while strict positions are seen as childish.
I think a lot depends on culture.
But let's look at the other end of the spectrum... can you imagine a parliament with hard core marxists, libertarians, nazis, and
@ChrisMayLA6 eco-fascists? Sounds like a recipe for disaster as well.
Maybe this is one of those "democracy is the best of the worst" truths, that are so difficult to change or tweak?