I imagine there's lots of administrative BS that goes on. There's the window for canceling, probably a few score/cheating investigations, a few test administration mishaps that need to be addressed (tests canceled for snow, fire alarms, etc.), and the usual batch of complaint calls from people who were unhappy with their test centers.
I don't know for sure, but I imagine that there is probably quite a bit of shipping involved to get the scantrons back. Finally, even with the miracle of modern technology I'm sure that it takes a LONG time to run all 40,000 scantrons through. And I'm sure there are the usual technological snafus that plague all offices.
Don't get me wrong: I'd like scores sooner, too. I just imagine that there must be a ton of logistical stuff that needs to happen. And, sadly, I'm so old that I remember when we had to wait for our scores in the mail 6 weeks later. And when we used to have to pay an extra $10 to call up and get our score through the automated telephone system. That was torture!
I also remember Atari, ditto machines, and using the school typewriter to fill out my college aps. Who's with me? Anyone else on here old like me?