The people at WWDC used to be cool. The last couple of years they've been drowned out by masses of people trying to cash in on iOS fads.
A lot of companies didn't even send their programmers last year—they sent their managers instead. The idiot managers don't even know WTF is going on. These people aren't worth talking to.
Witnessing a Steve Jobs keynote in person appeals to a lot more people than chatting at one of Apple's developer labs.
That plus the usual large-company conference boondoggle explains why WWDC has a lot of non-developer attendees. To make the conference 100% developers, either Apple has to get a lot less cool or the keynote needs to be moved out. Put the thing in Pac Bell Park and sell keynote-only tickets, and you'll get what you want.
A lot of companies didn't even send their programmers last year—they sent their managers instead. The idiot managers don't even know WTF is going on. These people aren't worth talking to.