Here we can see the state of the economy as reflected in the amount of schwag I've been able to get each year. Unfortunately, I didn't take a photo of the stuff from 1999, but let me assure you it was equal or more than what I got at the GDC 2000. (Note: schwag isn't a big thing for me any more after going to so many of these conferences).
2000:
2001:
2002
The decline of lavish spending can also been seen visually in the photos from E3 (including the ones I haven't posted yet). We're going to E3 this year and I'm really interested to see how it compares to past years, but I bet it'll be fairly low-key. More importantly, I want to find out who's taking over the Promised Lot -- arguably the best part of E3.