however apple may have it’s reasons.

1. discovered some last minute bugs ( fixable by downloads so no need to delay the os)

2. delaying while waiting for the chinese government to work out a better way to detect pirated software disks.

3. delaying to time the release with some other event like back to schoolanniversary(maybe apple was founded in october of the 80′s))

4 want to get anticipation high enough to worthy mass production of the minimum required by stamping factories and to insure a quick all at once financial return (hey apple if you need the money all at once now why not get a loan or a bunch of credit cards)

5. last minute legal concerns over a rumored feature (bit torrent sharing of the software updates for credits good at apple store(s) (hey apple go ahead and release the software and if you get a legal threat then temporarly disable the bit torrent sharing of updates).