Actually was just reading about this - basically in the US due to its size, logistically things were distributed early in the week to ensure that it was 'shipped to stores' by the end of the week as thats when retailers would target advertising and the like. Music/movies already had a Tuesday release date so games just accepted that considering they would be using the same pre-existing distribution channels...
Friday from a UK-centric POV seems to be the far better day for both consumer and retailer. Hell I bet people take more time off due to a Tuesday release than a Friday one. We seem to adopt Tuesday for worldwide releases but Id personally prefer Friday for those too...
ps3ud0