One thing to consider is market share. While one user switching from Windows to Linux won’t affect it one bit, but if, say, half of European Windows users would do the switch, that would cause a meaningful dent to Windows’ market share. So, while you won’t directly affect that number, you do belong to some circles of people. By making the switch, you would act as an example for others and bring some knowledge and expertise on the topic (like, how easy it was, what are the downsides/upsides…). If your example leads to other people do the switch, those people also belong to some circles of peoples, and so on. It might be enough to start a small avalanche that could grow bigger and bigger.