The development is still continuing, there are 10+ contributors with write access to all repositories in the organization. The only missing bit is permissions to change/add new team members to the organization.

There is nothing to take over, it would just be nice to not have to move the repository and notify the 700+ github forks of our repository to change the upstream.

I do not see the danger of abuse. This is not about a takeover by someone entirely unrelated to the organization and repositories. This is about transferring ownership of an established open source organization to those who already have write-access to all repositories and are in fact now running the project. This seems fair when the original owner can no longer be contacted for months. Why should the organization be forced to fork because of this?