> A lot of good video games have decent German dubs

This in my experience only holds for AAA titles.

For many smaller games, the German translation/localization is so bad that if one's English level is not insanely bad, it's even more comfortable to play the English version, and use a dictionary for lots of words (i.e. invest more time using the dictionary than playing the game) than tolerating the pain of how bad the German translation/localization is.