It's been confirmed on the Sprint GNex's device support page that it will receive the update starting today. A Sprint employee also confirmed on the NS4G forums that it will ALSO receive the update starting today.
GNex (LTE):
Find and update the software version on your Galaxy Nexus
NS4G:
Sprint Community: Jelly Bean Update?
Just because you don't have the update does not mean no one has it. Most people don't go posting on forums that OMG I HAS THE UPDATE Most people with this phone just have it because it was cheap or free and probably don't care about Gingerbread, ICS, or even JB. They just want a device to make calls, texts, and look at Facebook/Twitter on.
This means that every single person here (myself included) are in the minority as we actually care about what updates the phone gets and when. Some of us even root the phone and update the OS ourselves.
What am I getting at with this post? Most people aren't going to post that they have the update as they simply don't care / know this place exists.
If you want to equate this to gamers, we're the "hardcore" gamers who want graphics and story and blah blah blah, everyone else (read: pretty much everyone not on these forums, XDA, Android Police, etc) are the "casual" gamers who only care about simple games to play and beat, not about special graphics or features.
I'm going to go back to work now and wait patiently for the update. I probably won't get it until next Thursday anyway as it took Omaha, NE that long to get ICS previously.