Maybe we won't get them until our statements close?
Possibly, but I wouldn't hold my breath. A few months ago Amex suddenly gave everyone who signed up for the PRG card (the one for the University students) 40k points. Everyone got it on the same day.
If this wasn't done intentionally by Amex, then from a programming perspective I can speculate that the system was programmed to deposit the points no later than a certain deadline, and that deadline was most likely Jan 30, 2012. (But who knows?)