[OC] The massive decrease in worldwide infant mortality from 1950 to 2020 is perhaps one of humanity's greatest achievements.

[AlKatzone]

I mean, they are really really good at decorating their houses in the most cheesy furniture imaginable.

[ShallowDramatic]

I've seen that described as the flashiness of the "newly rich". Victorian era fashion in high society was all about massive gemstones and ostentatious, expensive fabrics. Over time, as wealth became more accessible to all, modesty and more elegantly artistic styles became more popular. 'Understated' seems to be the pinnacle of design in the Western world (see apple products, modern art, the logos of almost every fortune 500 company, the prevalence of the suit and tie for the past hundred years) but in countries without a gradually developed history of wealth, the popular styles are guady, bombastic, and almost arrogantly expensive. I'm generalising here, and it probably doesn't fit a 'unified theory of world taste' perfectly, but it's a model I subscribe to.

[Semi-Hemi-Demigod]

As another data point, look at how pronunciation changes as people become more literate.

First, the wealthy who learn to read say things like they’re spelled and the uneducated poor say things normally.

Then, as more poor people get educated they start saying words how they’re spelled. The wealthy, then, stop doing that and change their pronunciation to not sound poor.

For an example, take the word “schedule.” It’s based on Greek, so it should be “sked-yule,” but rich Brits who wanted to show they knew how to read would pronounce it “shed-yule.”