In fact it does make me wonder what sort of plans exist for retrieval of the seeds presently stored in deep freeze.
But you have to imagine the pyramids as recovery vaults would require the participation of the populous at large as apposed to today when a government or rich individual could have a sanctuary or vault built with virtually no-one knowing.
Which means the Egyptian public either believed in the project, were forced to accept it, or were under the influence of a master level public relations campaign. Or most likely, all the above. Just as happens today.
Regardless a recovery vault must have had a recovery plan. And that plan would have been kept somewhere both safe and retrievable after an expected disaster.