This is for last minute edits. SS08 was to be SS07 but it had last minute edites then by that time, 2007 was nearly ended so they had to move it's release date to get it ready.
Last minute edits? Far from last minute.
VSTEP gave out a estimated release time, it's still estimated.
In the gaming industry game developers may have a struggle with a particular feature of the game or adding another feature or they are also focusing on other projects aswell, not only that bug testing also takes a while and well, no game designer can give a accurate date for when that finishes therefore the release date is a complete estimate. Some releases are delayed.
Since the first teaser came out, the estimated date has changed. The fact is, this happens with most game developers.
Last minute edits is merely the main reason, well most of the time anyway..
