I'd be careful around claims about cultural identity and homogeneity. A lot of countries, like the scandinavian ones and NZ (and Australia) can look that way from the outside, but I think its a simplistic view. From our perspective, for example, apart from the obvious catastrophic partisan politics that have gripped the US, the US looks like it has a united cultural identity (e.g. a religious devotion to the founding fathers, patriotism, commitment to freedom of speech etc).

There was a recent article where a citizen of a Nordic country got upset at this common view, pointing out that perhaps it seems homogeneous to the US because in the US, today, you are white, black, hispanic, asian etc. There are not strong subdivisions in these categories, it seems, and subsequently they apply this view to other countries. But in Europe and Norway, Sweden etc, there are many flavours of 'white' with a long and recent history of animosity.

NZ is a country with a large indigenous population (the Maori), a lot of pacific island immigration, and increasing and accelerating immigrant population of Indians and Chinese (among others). These all assert social pressures of their own, and I would argue its partially our social safety net and maybe certain aspects of our culture and economic structure that have allowed it to be (mostly) harmonious, so far.

Not saying your entirely wrong, but that it is not (no pun intended) black and white.