The purpouse of this scheme is to keep a low demand during the initial days of the Landrush.
We dind't want to build a whole new system to be used just the first week of landrush, but we needed to keep our systems up and running regardless of the ammount of requests.
Bare in mind that all the price announcements apply only to NIC Mexico Registrar, and that we have 180 more registrars where you can register the .MX domain names (sometimes cheaper than us)
Registry .MX: Consulta de Registrars de Nombres de Dominio .MX
Finally, the one thousand USD price will last a week the most, as soon as we are sure we could go down the next step (in price) we will lower it.