Source..?
This happens with *most* games, not all games.
So unless you have a source from Steam of Bethesda saying you can do that for Skyrim, aka preDL it before november 11th, my statement stands true.
Each of the last few games published by Bethesda were available for download in advance on Steam and then unlocked on the release date. The purpose is not so much to provide a convenience for customers, but rather, to reduce the bandwidth demand on Steam's servers.
IIRC, Fallout New Vegas, Brink and Hunted unlocked at 12:01am PST.
RAGE unlocked at 12:01am EST (for US/Canada market).