If I'm going to guess (and I am), this *seems* to mean they will stop making new codexes. They will re-do all the existing ones and then stop. After that it will just be campaign books/special formation boxes, and such. Two years seems a reasonable timeline in which to do that. I don't even find that idea terribly objectionable. It would be nice to work within a set group of army rules for a while.
And I also don't believe it for a minute. "Forever" in business terms is just "so long as we make money not doing it." If Age of Sigmar tanks, for instance (and it probably will), expect to see the "triumphant return" of more traditional WHFB inside of a few years. They might keep the world blown up, but they'll go back to army books, regiments, the whole bit.