First of all, you have to realize that it's impossible to measure inflation and purchasing power objectively. It always depends on a highly subjective (and gameable) basket of goods. But inflation and purchasing power are a thing, so it's a bad idea to ignore them. You just have to keep in mind that all these economic time series are a lot less accurate than they seem.

But if you want to account for purchasing power, it doesn't make sense to ignore inflation. So the "GDP, PPP (current international $)" data which the article refers to seems mostly useless to me. You really have to adjust for inflation as well (constant $) and the picture will become quite clear:

https://data.worldbank.org/indicator/NY.GDP.MKTP.PP.KD?locat...