This goes back a lot further than computer icons. Road signs for railway crossings still show steam trains. Men/Women signs for toilets show women in skirts that nobody wears, on images that hardly resemble people at all. My car has a snowflake for the AC button, even though snow doesn't come out of the vents when you switch it on. Interestingly, signs that ban music players in certain areas now look like Gen 1 iPods…
It demonstrates to me that it doesn't matter what the icon is. What matters is convention. Nobody has to ever see the original as long as there is universal acceptance about what the icons mean.
I've wondered how non-english speakers learn Java. I don't think they really have to know what the translation for `public` and `class` are as long as they understand how they work.