I’ll admit I may not understand economies well, but the inverse is that these publishers are enabled to charge higher prices in higher-income countries. The cost of creating their goods is constant, so if Valve isn’t selling at a loss to poorer regions then they are simply extracting additional profit from higher-income regions on the assumption that those customers can afford it.

I wonder how this kind of scenario plays out in other industries. Regardless, it seems like the EU has a goal of reducing gaps in buying power between their members, and their unified digital market is a step in that direction.

Did you read the article? This isn’t comparable to your India vs America example, it’s specific to prices only within the EU where the EU has digital market rules that specifically prohibit this.

What Valve did does sound like price-fixing too according to your linked definition of “an agreement among competitors to [fix] price levels”:

“Valve and five publishers (Bandai Namco, Capcom, Focus Home, Koch Media and ZeniMax) agreed to use geo-blocking so that activation keys sold in some countries … would not work in other member states. That would prevent someone … buying a cheaper key … where prices are lower.”