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Seriously, why do companies do his? Is localization too much work or something?
The short answer comes down to expected revenue, and expected support, sometimes with a side of "commerce politics that don't quite make sense from the outside."
Remember when Steam lowered the boom on cross-region stuff? The move was hot on the heels of the russian ruble taking a nosedive, iirc. In this modern networked world, that would've given any enterprising ru.gamer an easy way to make brain dead easy cash for flipping game copies. Letting someone have your revenue/profit doesn't keep the business healthy.
Localization, done well, is not cheap or easy. Also, having someone yell at you in broken english or a language you don't speak is a little terrifying... tech support staff generally don't get paid enough to deal with that.
The political bits are harder to see sometimes.
South Korea is a heavily PC-focused country, because there was a ban on Japanese electronics for many years (caused by Imperial Japan having Korea under its boot-heel for a couple generations).
China is also heavily PC, but for wildly different reasons. Their console ban started in 2000 after public outcry re: video games as a negative influence. It didn't stop any trends, it just altered their courses a little. The ban was loosened in 2015 when PRC finally figured out they like money, and can still ban specific games that don't pass muster.
Brazil has a weird history with games. I don't recall anything ever being banned outright but heavy tariffs, currency differentials, and low citizen wages make it an unattractive official market. I've heard the grey market is doing pretty good there, though.