I wouldn't be surprised if there are a substantial number of reservation holders who don't know they can order now. That may explain why the non-response rate is over 25%.
Reason #1: from what I am reading on the forum, those ordering did NOT get an e-mail as they were promised but discovered they could order by looking at their "dashboard." If I weren't reading this forum I wouldn't have known about the dashboard and would be waiting for an e-mail that might never come.
Reason #2: my guess is that most people aren't being contacted by any dealer because they didn't ever select a preferred dealer or give any the right to contact them. I think the default is no contact unless you opt in. The Nissan website does NOT make clear what you are supposed to do unless you dig for it. I didn't know I was supposed to click on My Account and choose a dealer until I read that here on this forum. I thought that was like any site from AOL to facebook where you just put in name and contact info, like email, and maybe you usually lie about some of it for privacy reasons, and then wait for them to email you. I have been getting the promo e-mails regularly, so I would definitely have expected to receive an email letting me know I can order. The same is true for knowing to check the dashboard; I learned about it here.
Reason #3: maybe I'm wrong and most of you who have ordered did receive the email relatively promptly, but I wouldn't be surprised if some others got those shunted to spam and never saw them. Nissan should really give the nearest dealer the right to call up the non-responders after a period (2 weeks, maybe?) and ask if they are still interested, no hard sell. If they aren't sure, leave them on the list, but some will say no, they already bought something else, etc. Take those folks off the list.
Reason #4: there are always some who just get on a reservation list to keep their options open, and were never committed to the car, or who now can't commit for financial reasons. They're probably undecided and aren't ready to request the $99 back, but want to wait for the Volt, or a test drive of the Leaf, or becoming re-employed, etc.