Apple does seed the Mac OS updates, at least, and I was running 9.0.3 and then 9.0.4 for some time before it was released officially. My G4 came with 9.0.2.
Unfortunately the DVD software and QuickTime 4.1.x was not "seeded" to developers recently, or ever, as far as I know. They would have found the problems if they had, I bet.
I am sure Apple is aware of the problems, but really can they hold up a needed OS update because of a spurrious DVD decoding/synching problem? They can always work on it with their newly acquired DVD authoring team and release *yet another* update.
Software decoding sucks, we already know this. Is watching a DVD movie so critical though?
Spend 1/10th the moeny on an iMac and get a DVD player and plug it in to the tv and your stereo, it will be a lot nicer to watch.
For the record I didn't notice a problem with a DVD "popping" before 9.0.4/DVD 2.2 and afterwards (in The Sixth Sense at least) there is popping at least once a minute on audio and it was out of synch really bad by the time Cole says "I see dead people".