Idk about the Polish and Germans personally, but for the Netherlands at least it’s a relatively small country with a limited amount of entertainment made there, so a ton of media is imported and subtitled. Since a lot of it comes from the US and UK, and most of it is subtitled (for the most part only kids’ shows are dubbed over), the majority of people speak or at least understand English. According to Wikipedia, it has been estimated that as much as 90% to 97% of the population is proficient in English.