They may not want to announce their next title so far in advance. But, that doesn't mean we won't see something at the end of next year.
They released Dragonborn, the last thing they developed for Skyrim, on December 4th of last year. That means it was finished by mid-November at the very latest and probably earlier. While some of the engine/optimization people were working after that trying to get everything to work with the PS3, the world/quest building people were effectively finished with Skyrim by that time. They haven't been laid off and they haven't been paid to remain idle. They have been working on something for the past year.
Bethesda Game Studios builds huge open world RPGs. They have two franchises, the Elder Scrolls and Fallout. Unless they working on a third, brand new franchise they have to be working on one of those. An Elder Scrolls title is unlikely immediately following Skyrim and with Zenimax releasing ESO next year. A new Fallout title is the overwhelming probability.
How long will it take them? Late next year would be about right given their past development cycles, but this year we have seen a new generation of consoles. Developing a next generation game that truly takes advantage of the increased capabilities of these new, more powerful systems may take a little longer than their past efforts took. I don't know enough about it to say.
Not hearing anything at the VGA's doesn't mean anything. The site(s) ultimately proving to be a hoax doesn't mean anything. It will come, and even if it arrives late next year it's too early to be getting excited about it today.