I think you are confusing a lack of populism with homogeneity of thought/culture. Your examples are all pretty small countries with little cultural divides. Even NZ got pretty populist on immigration when the number of immigrants started to increase, and Denmark literally was the harshest on refugees; they literally sent them all back a few months ago now that they say Syria is safe enough. Sweden is another example where populism went through the roof seemingly out of the blue, considering its historically consensus/trust based democratic system, for reasons similar to almost every other country in Europe. If Sweden went that way, I'd think any country could.

If anything, I think your examples prove why populism is inherent to truky democratic systems. To me, it's actually a sign of a well functioning, diverse society not only demographically but also ideologically. And that's imo pretty healthy - at least much more so than a permanent homogenous consensus.

(And in a democracy if elected politicians don't align with voters under the pretext of not bending to populist demands, someone else will do it. The job of politicians in a democracy is to represent the electorate, not the opposite.)