Menzoberranzan will be (mostly) edition-neutral. Should there be any further publications before D&D Next, that's likely to be the case for them, too.And what about Menzoberranzan in August? Not to mention any products they haven't unveiled yet?
I don't recall where or by whom, but this was mentioned by a WotC representative at some point.
Apart from the DDI, 4e support is pretty much done. Which is really a pity, imho, considering it's my favorite edition and D&D Next sounds like a step back.
Considering the results of a recent poll in one of Chris Perkins' articles (about the usefulness of various books from a DM persective), I can understand their decision, though. 4e Sales seem to have dropped noticably over time, no matter what the quality or topic of the books was. The Essentials line didn't seem to have done anything to reverse this trend. (I'm concluding this by looking at the percentage of votes for the 'no opinion/don't have it' option when ordered by release date).