I wonder if this is another 'big in China' effect, similar to how China was the last big holdout for WinXP in the Steam hardware stats until 2020 or so after Microsoft had dropped extended WinXP support in 2014. When we tried to decide whether we should drop WinXP support from our MMO game client after Microsoft pulled the plug we monitored the Steam hardware stats for a couple of years and from time to time there was a sudden surge of popularity for WinXP at the cost of Win7 and Win10. We explained that to ourselves that another wave of Chinese PC users must have entered Steam (maybe because of a popular game release in China which was entirely obscure in the rest of the world).