Last year's Dear Friends did sell out at this same Chicago location, and the place was crowded enough to prove it, so everyone did show up.
For this year, even though the VIP for Chicago has sold out, I too am surprised there are still lots of regular seats left... Maybe some people now have a "been there done that" feeling, even though it's going to be completely different songs here than all FF...
Or maybe it was just the strength of the FF fanbase that sold the Dear Friends quicker, and people might not be as excited about "other vgm" it's hard to say... But at any rate we're getting to see real market analysis in action as to what people really do attend and don't attend.
(off-topic)
And speaking of attending, it seems the One-Up Mushrooms are playing a live gig in Arkansas on the same day (May 27th) and they've still got ~275 of their 300 seats available, so that's only like 25 people paying to show up to there (ouch!)
A quick browse of their messageboards shows that their fan demographic is mostly teens who need their parents permission though (14-19) and their parents are putting the smack-down on driving to other states with a bunch of other online guys they've never met before.
The last Chicago concert had a pretty diverse age demographic, so that shouldn't be the issue for PLAY, while it might be that people just can't spare as much in 'travel money' these days for ANY type of roadtrip...