Cares
This was my exact experience last year when applying. USC had absolutely 0 effort when it came to "courting" me. I already received multiple e-mails and an acceptance from Anderson before I even got an interview request from USC. I withdrew my application because they took too long and I did not enjoy the process whatsoever.
Thanks for confirming what I suspected. FWIW, I called the Admissions Office today. Someone picked up on the first ring, and he was very polite and professional. He said that a lot of the admissions directors are traveling internationally right now for recruiting, so things might be a little delayed. He also explained that they are still sending out interview invitations to the applicants who applied when the application first opened on September 1, so I am behind them in the process (makes sense).
Overall I'm still disappointed with the slowness and lack of proactive communication about the process or any attempt to "recruit" me, but I was impressed with the AdCom rep I spoke with today.
It seems that based on the timing estimates I heard today, I will have a decision from UCLA Anderson before I even get an interview invitation (assuming I would get one) from USC Marshall. That's a little frustrating given that my Marshall app went in well before the Anderson app, but... nothing can be done at this point, except to keep waiting.
As always, best of luck to all applicants! Please post if you receive any news!