Al Qaeda Home Videos: bin Laden’s Epitaph?

Brief thought of the day: The recovery of the al Qaeda videotapes appears to be me to be the most convincing evidence yet that bin Laden is, in fact, dead.
Consider:
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.