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.