Al Qaeda Home Videos: bin Laden’s Epitaph?

Brief thought of the day: The of the al Qaeda videotapes appears to be me to be the most convincing evidence yet that bin Laden is, in fact, dead.
Experts seem to see this cache as highly significant at least, and quite possibly bin Laden’s personal library. CNN has indicated that they obtained them from a source who found them in a house bin Laden had previously stayed in.
So: one can presumably understand that bin Laden or his close associates might abandon the cache in haste to depart the scene in Afghanistan.
But: why, then would bin Laden and/or his top aides never bother to send somebody — anybody — back to retrieve the tapes?
Unless, perhaps, everyone who knew of the tapes last location was, in fact, dead dead dead.